Disclaimer: I own none of this. The BBC does. I'm just borrowing.
Fitz couldn't sleep because the Doctor could.
The Doctor claimed that he didn't require as much sleep as humans did - only a few hours each week was enough, he said. But his sleep couldn't be very restful if the noises coming from the room next door were any indication. They kept Fitz awake, and a sleep- deprived Fitz was a miserable Fitz.
Miserable Fitz stood now in the corridor outside the Doctor's room and wondered what he could do for his friend. It was quiet for the moment, but he knew it wouldn't last. It never did. Any moment now the screams would come again, anguished cries that echoed through the gloomy hallways and penetrated every room. There was no escape.
He didn't want to think about his friend's nightmares. When the screams woke him this time, Fitz had got up and lit a cigarette, trying to distract himself. It wasn't working. He puffed and paced, eventually finding himself standing by the door to Doctor's room. From behind the door came howls of unimaginable terror. He considered barging in there and rousing him. That way at least one of them could get some restful sleep. But what kind of callous monster would that make him? The Doctor was reliving heaven knows what kind of soul-shredding torment, and Fitz could only think of how it affected his own comfort? No. That wasn't him. Not anymore. He shuddered as another scream tore the air.
The Doctor never screamed when he was awake. Or if he did Fitz had certainly never heard it. He maintained a cool composure through situations that would turn mere mortals into quivering blobs. And when he wasn't being Mr. Cool he was a savage wit, serving up humour and tea with equal aplomb. Fitz envied him. Tried to emulate him sometimes, though he suspected it was impossible. A roar of pain faded into a whimper and Fitz grimaced. He didn't envy him now.
He thought back to the first time it had happened, just after that horrible business on Anathema. The Doctor had needed more sleep then, in order to heal his injuries, and had nodded off on the sofa beside the TARDIS control console. Hours later his screams woke Fitz, who stumbled bleary-eyed into the room to find the Doctor on the floor behind the sofa, curled into a tight foetal ball and mumbling about Daleks in his sleep. He tried to put on a brave face when Fitz woke him, saying it was "nothing", and "just a dream", but the haunted look in his eyes made it clear it was more than that.
Over time, as his body healed, the nightmares got worse instead of better. Compassion, as usual, was less than compassionate. After her transformation, she insisted that he do all his sleeping in his own room. She didn't want him to do anything to "her" controls while sleepwalking. Fitz wouldn't be surprised if she locked him in there at night. But then, Fitz wouldn't be surprised if she decided to lock both of them in their rooms all the time.
What must it be like for him, he wondered. Everything he'd ever had, gone. Well Fitz could sort of relate to that - everything he owned was gone now too. Even his guitar. He missed that especially. But the Doctor missed more than possessions. He and the "old girl" had shared a telepathic link. At times it seemed like the TARDIS was his best friend; at other times it seemed to be part of the Doctor himself. Now that link was severed forever. What did that do to a Time Lord?
And speaking of Time Lords, the three travelers were now on the run from them. Like they didn't have enough to worry about already. Fugitives from the most powerful race in the universe, Fitz thought gloomily. This can only end badly. The screams echoing around him seemed to confirm this bleak assessment of the situation, though when he was awake the Doctor seemed certain that they'd continue to evade their pursuers. He'd done it before, he announced confidently; he could do it again.
The mournful sobs were more than he could stand. "Can't you do anything for him, Compassion?" he hollered at the ceiling.
When she replied he wasn't sure if he was hearing her with his ears or in his head. "You know I can't." The voice paused as if to reconsider. "Well maybe you don't know." Then she said some things about dreams resulting from the subconscious attempting to impose order on uncoordinated streams of data. About neural core dumps and artron energy and lots of other things Fitz didn't understand. Even that failed to put him to sleep.
"Do you dream, Compassion?"
"Of course."
"What do you dream about?"
"You couldn't begin to comprehend what I dream about, Fitz."
"Gee, thanks."
"No, really. If it's any consolation, the Doctor couldn't comprehend what I dream about either. I don't think there's another being in the universe who could."
"Oh." Fitz was touched. The casually cruel Compassion was actually showing a human side. Which was ironic, as she was about as far from human as one could get. Maybe the Doctor's torment was bothering her more than she let on. He found himself wondering if she had a telepathic link with the Time Lord.
"I can't help the Doctor with his nightmares, Fitz. If he's got personal demons to exorcise, or trauma to work through, he'll have to do it alone."
"I see." Fitz didn't see. Trauma he could believe - the Doctor had seen plenty of that. But personal demons? He thought about the kind and caring man he traveled with - now sobbing inconsolably in the next room - and couldn't imagine that he had any skeletons in his closet. And even assuming that he did, why should he have to confront them alone? He helped others everywhere he went - it seemed horribly unfair that there was no one to help him now.
"Believe me, if I could just go into people's minds and change things around," she said, "the Doctor is not who I'd start with. You, on the other hand..."
"Oh very funny."
There was no reply. "Compassion has left the building," he groused. Well call me a callous monster, but if I'm going to get any sleep at all, he's going to have to wake up. Fitz went to the door, intending to rouse the Time Lord.
He stood with the knob in his hand, bewildered. What he was sure had been the door to the Doctor's room now opened into a closet. With a life-size skeleton hanging from a coat hook. Very funny, Compassion. What was behind the skeleton, though, made his face light up in a grin. There, in all its scratched and battered glory, was his guitar. Or a more-than-reasonable facsimile thereof, he thought. He carried his prized possession back to his room, sat on the edge of his bed and began to tune it.
A few power chords oughtta drown out Screaming Mimi, he told himself, striking a Rock God pose. His hand sagged. He couldn't do it. Fitz you old softie, he thought. He returned to the bed, sat down, and plucked out a halting Brahms' Lullaby. No, that was all wrong. It didn't suit the mood any better than power chords did. He could do better.
He needed something that was soothing without being all sweetness and light. Something with tension and release, just like real life. Somber but not menacing, and in a minor key. He noodled around, improvised on the theme, and by the time he was done he had one passable Fitz Kreiner original to show for his troubles and parts of two more. A good night's work.
He yawned, put the guitar down, stretched out on the bed and closed his eyes. For the first time in hours the room next door was blissfully quiet.