There were times when Baymax suspected he might be malfunctioning. Self-diagnostic returned no errors, but he could still detect anomalies; he had not yet decided whether his diagnostic was part of the malfunction or if there were simply things about himself he failed to understand.

He understood the parameters of his programming to a degree. He had enough initiative and curiosity to seek further information on a problem and from there devise a solution if one was not already programmed; he had a distress response to a patient's distress; when a patient was satisfied, his distress lowered in kind and was replaced by what he sometimes thought might be satisfaction too.

He understood his physical capabilities precisely as well as he needed to for caregiving (and for karate, which he supposed was close enough to caregiving with Hiro depending on him for defense in the field). He could lift a thousand pounds on his own and many times that with his armor equipped; he was slow on his own but his armor made him quicker as well as stronger and very fast indeed in flight; he had a sense of touch in the form of pressure sensitivity that allowed him to avoid either applying or receiving damaging pressure.

Baymax inflated a bit more than strictly necessary and then released the excess air in a heavy sigh, imitating his human companions; that too was strange, and the careful inventory of what he knew for certain had only thrown everything else into sharper relief.

He could pinpoint the moment curiosity meant for medical pursuits had been piqued by something decidedly non-medical - it had been a movie he caught a glimpse of while Hiro tried to herd him downstairs. (He still had not seen that movie despite several evenings on the couch with the Hamadas; he would have to ask later.)

His distress was still always in relation to the humans in his care, but he could pinpoint the first time it had been deeper than a simple need to care for them: Hiro, perilously close to the portal over Krei Tech, his grip slipping by the second. Baymax had responded in a way that he was not certain could be termed mere 'distress'.

The first time he had been satisfied in a way unconnected to a patient's immediate well-being was more difficult to pinpoint, because he found that an astonishing number of things were satisfying. Flying was satisfactory of course - satisfactory enough when he was alone, exponentially moreso with Hiro's slight weight on his back and exhilarated laughter ringing above him. Hiro's startled delight the first time he used an expression correctly was satisfying, as was Hiro's clear pleasure and amusement any time Baymax explored the numerous ways one could make use of words (and what one could do with words sometimes satisfied Baymax in a way that he thought might be a sort of amusement too). Holding Mochi and listening to the rumbling he made ('purring' according to Aunt Cass - and he was satisfied that she never objected to him addressing her as 'aunt' when he'd begun to do so after she'd fussed over punctures in his vinyl in nearly the same way she fussed over Hiro's frequent scrapes and bruises) was satisfactory. There was something satisfying in both his increased strength and mobility in armor and in returning to his normal state as Hiro or one of the others helped him shed the armor, and the contradiction was a puzzle that was satisfying to mull over (which was a puzzle in itself).

And aside from his interest in his varying physical abilities, he had noticed that he began to hope for certain types of pressure. It should have been all the same to Baymax - initially, it had been - but there was a difference now, and he found himself looking forward to Hiro flopping against him or Fred running up to bounce off of him or Aunt Cass's and Wasabi's light pats or the affectionate brush of Honey's hand or an equally affectionate swat from Gogo or the way all of them leaned into his hugs. It was satisfying, and something he sought in nearly the same way he sought to aid them, a blend of mood and pressure response he did not know what to make of.

It was all well beyond the expected responses and processing of a healthcare companion. Baymax had asked Hiro before if the current path of events were what Tadashi would have wanted; now, he was asking himself the same.

Unlike Hiro, he had no answer.

"Everything all right, buddy?"

Baymax blinked. Hiro was looking at him now, the boy's attention captured by Baymax's sigh (why had he done that? It did not fit in with any of his known functions).

"Yes," he said after a moment. "All is well." Baymax was not entirely certain this was true - a realization that gave him pause, as he should not have been able to say anything that might be deemed untrue - but he saw no reason to worry Hiro just yet.

Worry. Yes, that was the proper term for the distress brought on by the idea of malfunctioning.

Was he meant to worry about anything but his patient's current state?

Hiro was still watching him, puzzled but not yet worried himself. Hiro never worried about what Baymax did unless there was a chance it might get them in trouble; Hiro always took Baymax's behavior and moods - if that was the proper term for them - as if they were exactly how things were supposed to be.

It was satisfying - a type of satisfying that might be termed comforting perhaps? - because there was no one in the world who knew Baymax's inner workings as well as Hiro. Therefore, Hiro would surely know if something was wrong with him. That comfort didn't quite overcome his worry - yes, he was almost certain it was worry - but there would be time for that later; Hiro was still watching him, waiting for him to elaborate.

"Are you... bored?" Hiro asked. "Can you get bored?"

I am a robot. I cannot be bored.

Was that true?

It had been. Currently, Baymax was... distressed by the question? No - uncomfortable with it.

"I do not know," he said after a moment. Hiro's gaze was curious, fascinated, but still lacking any trace of worry; Baymax shifted his weight and looked toward the bedroom door. "I am not currently bored. But it is nearly your usual mealtime. Perhaps we should go downstairs."

That got the desired result. Hiro - prone to forgetting to eat when buried in a project - immediately decided he was hungry and leaped from his chair to head downstairs. Baymax followed, satisfied.

Relieved.

It seemed he was experiencing quite a few mild-but-distinct variants on his programmed 'distressed' and 'satisfied', and he wondered again if that strange branching-off was what Tadashi would have wanted.

Baymax had already developed some skill in reading Hiro's emotions without a scan - his moods were swift-changing and extravagant, close to the surface even in his occasional bouts of nerves or shyness, and Baymax had quickly decided that this could be attributed less to pubescent moodswings than to Hiro's own energetic personality.

He decided that observing other humans and learning to read their moods as naturally might help him better understand what was happening, and therefore allow him to better explain himself if need be.

Aunt Cass was the easiest, partly for the sheer amount of contact and partly for being similar to Hiro; Baymax drew satisfaction from catching similarities of inflection and expression that both reminded him of Hiro and gave a clue to her mood. Fred and Honey were similarly easy, both bright and open. Wasabi was a bit more difficult, his moods a bit more restrained but prone to quick outbursts; Gogo was harder still, reticent enough that sometimes only the slightest hint of a smile or frown betrayed her emotion.

Abigail was usually as bright as Hiro or Fred or Honey, but there was often a contrariness in her emotional expression - it took Baymax several tries to determine when she was genuinely annoyed by something and when she was pretending for her own amusement.

Huyen Phùng, Krei's often-silent personal assistant, was surprisingly easy to read if carefully observed, her expressions and posture shifting subtly but clearly.

Krei himself was the most difficult human Baymax had frequent contact with, nigh-impossible to read without a scan and often baffling with one; his smooth confidence seemed to be genuine but so did the current of anxiety running under it, and while he was at his most relaxed speaking to Aunt Cass or Huyen or Abigail his conversations with Abigail in particular were often punctuated with brief spikes of temper that made him... happy?

Baymax began to suspect that no amount of careful observation would help him make sense of emotional response. He also began to wonder how often humans could make sense of it.

As it was, he was no less puzzled than he had been when he started - though it had been satisfying practice in interacting with humans.

Besides, he had noticed another potential anomaly - one that certainly affected his programming, though he was uncertain whether it had to do with emotional response.

As with most of the strangeness, he could pinpoint the first incident. It was something Baymax thought nothing of at the time, though it had certainly startled Hiro - for Hiro's sake, he had wanted to deny him the ability to further alter Baymax until the boy was calmed.

It had worked. Baymax had successfully denied access to his data cards. He had disobeyed, something he had nearly forgotten in the flurry of events that followed.

Of course, forgetting made no sense. Perhaps his main chip had sustained damage; it would have made a satisfactory explanation for current anomalies if not for the fact that some of these responses had begun well before then.

Perhaps he had not so much forgotten as been reluctant to consider the implications - another sort of distress, he supposed, treading close to worry.

Either way, he not only had these strange responses but could act on them. Normally he kept this restrained; it was not necessary, and the idea that he could make that decision if need be was enough to satisfy him.

His thoughts on the matter were interrupted when Hiro briefly shut him down to allow his internal drives to recompile - Baymax did not need sleep in the way humans did, but short respites were helpful to keep his systems running properly - and when ready to leave the lab he absentmindedly called 'come on, Baymax' instead of his standard flippant 'ow'.

Baymax, still vaguely aware even in shut down, had tried to respond both because he did want to follow Hiro and because of an alien impulse to simply see if he could; to his satisfaction he was fully active again in seconds, hurrying after Hiro as the boy slowed his steps to allow Baymax to catch up.

Hiro either didn't notice the anomaly or failed to remark on it, though Baymax did catch sight of Wasabi watching him with a wide-eyed, considering gaze.

Wasabi's shock was harmless enough, and strangely satisfactory. Baymax decided that he was in fact capable of amusement, and amused at this, and if his assessment of his response was incorrect there would be time to correct it later.

He did still wonder if this was what Tadashi would have wanted; he was beginning to consider that perhaps it was something Baymax wanted, and to consider the implication of wanting anything at all aside from his patient's satisfaction, but Hiro was sprinting across the courtyard and shouting for him to watch as he bellyflopped into a pile of autumn leaves and there would be plenty of time to consider it all later.

The question remained somewhere in the back of Baymax's processes for the next week.

He considered the difference between being a good healthcare companion and simply being a good Hiro companion. He was surprised at the small ways they sometimes contradicted each other, and by how, when he mentioned the matter to Aunt Cass, she only laughed and said she was glad someone understood the problem - after all, he could not honestly say he did understand and was not certain she entirely understood either.

He did know they both tried, and that this trying brought a strange combination of satisfaction and distress to them both.

He watched Hiro, as always, take anything he did in stride, as something natural; he watched the others sometimes give him considering looks, never quite worried but often intrigued.

He tried to categorize his shades of satisfaction and distress, comparing them to observations of his companions (even iftheir responses sometimes came in more nonsensical combinations than even the tug between healthcare companion and Hiro companion could induce).

Tonight, he had a few shades of distress to deal with. Hiro was studying for midterms and Baymax had been informed that, while the professors were willing to tolerate his following Hiro to class, he would not be allowed to sit in exams; Baymax understood the sense of this, and that he could not constantly shadow Hiro, but he nevertheless decided his response to this was best termed irritation (in part due to having realized they thought Hiro might cheat). More than that, Hiro - almost desperate to excel in all classes, even those not directly connected to his major - had been at work all day, spending a crisp, bright fall afternoon jumping from project to project and going over notes and demanding periodic quizzes from Baymax.

Unhealthy, Baymax had decided - a verdict that both the Healthcare Companion and the Hiro Companion agreed on.

"Hiro. You have been working for over nine hours without pause."

"Yup."

"It is time to take a break." Baymax paused, considering, before speaking again. "Perhaps you should go downstairs," he added. After all, a break at any of Hiro's workstations was hardly likely to be a break at all.

"Later," Hiro mumbled, squinting at his notes. "Little bit concerned about Lit here..." He trailed off in a vague grumble; Baymax inflated slightly and sighed.

"Your well-being is my concern. You are my..."

He paused, considering his words. A programmed stock statement was no longer the whole truth of this; Baymax tried to pinpoint the moment this had happened, and could not.

It did not, he concluded, truly matter.

"You are my friend."

Hiro did notice the anomaly this time. He had looked up when Baymax paused, a question in the quirk of his mouth and the slight lift of one brow, and for a moment the idea - the worry - that he might be malfunctioning flickered again at the back of Baymax's mind.

Then Hiro smiled, warm and wide and wondering, and pushed away from his desk.

"Well then, uh... all right. Well-being it is. C'mon, I'll show you that movie you were asking about."

Moments later, huddled on the couch with Hiro and Aunt Cass and Mochi and filled with the low, gentle satisfaction he had decided was better termed contentment, Baymax wondered again if this was what Tadashi would have wanted.

Ultimately, he decided that while Tadashi might not have intended these responses and functions he would have surely been pleased at how Baymax's programming had bloomed.

And he decided, for whatever it might be worth, that it was absolutely what Baymax wanted.