Jack may not have understood anything about the bomb, or what Mac was saying, but he understood his partner. Probably more than anyone else, so when Mac started to slow down he noticed.

He noticed the way Mac was breathing a little harder than usual, tired arms wiping the sweat from his forehead with the back of his hand. Jack also didn't miss the fact that those hands, that were usually so steady, were trembling just a little.

He noticed all these things, but he didn't say anything. He wanted to, he wanted to make the kid sit and eat something or drink a little. But when faced with the lives of half of downtown LA, he had to push his concern aside and just let the kid do his thing.

Jack's job was to take care of Mac, and ever since he'd met the scrawny blonde kid back in the desert, he'd taken that job seriously. Even when they were at home, or on one of their extremely rare holidays, he was still looking out for him.

He had gotten pretty good at it over the years, and it was just second nature at this point.

So, it did not escape Jacks notice that Mac hadn't had anything to eat or drink at all that day. Even before the whole bomb fiasco Mac hadn't eaten anything but a muesli bar, and that was only because Jack had shoved it into his hand while he was fixing his bike.

It had been hours since Mac had even taken a sip of water, and Jack was worried. Mac, of course, didn't notice, too preoccupied with saving everyone. And Jack knew that Mac needed to focus, but he also needed to be able to stay on his feet while he disarmed the bomb.

He'd tried, once or twice, to push at least water into Mac's hand, but there was too much going on in that blonde head to think about something as trivial as his own health.

"Here." He held a glass out and Mac turned, forehead creased concentration.

He only looked at the water for a second, before gesturing across the room.

"No, thanks. Hand me that screwdriver?"

Jack knew better than to try and push food on him and resigned himself to just watch over the kid while he worked.

He knew Mac was stressed out, and he had reason to be. The man that killed his mentor had broken into his house and wired a bomb to the whole place. His home had become a very dangerous prison, and if he didn't find a way to disarm it, he could kill more than just him and Jack. There was a lot on his shoulders. But wasn't there always?

Jack watched Mac's hands tremble as he played with some wires.

"You got this, Mac."

Those blue eyes found his, wide and afraid, but Mac smiled anyway as Jack thumped a comforting hand on his shoulder.

Jack knew Mac was putting up a brave front because he was doing the same. And as the night wore on, it became more obvious that Mac's blood sugar was getting dangerously low.

He was sweating and shaking, wiping his eyes tiredly every so often, but the real worry was when he started muttering things out loud and then writing them down.

Jack stepped out of the way as Mac stretched over the bench to grab a pen and paper, scribbling equations and formulas over the page.

Over the years, Jack had seen Mac scrawl over any surface he had near, in order to work through whatever was going on in his head. Walls, windows, Jacks arm at one point when they were out in the forest with nothing for Mac to write on. But those were complicated equations that he hadn't done since MIT. This was stuff that Mac had done in his head a million times.

Mac was almost too familiar with bombs and explosions, so the fact that he needed to write down his equations told Jack that the kid was not only tired, but he was having trouble concentrating.

He frowned as he watched Mac scribble out his line of numbers and start again.

He would take care of Mac but he had to wait until the bomb was disarmed, and he hated it. He wished, not for the first time, that he was smart enough to help Mac, so that he didn't need to do it all on his own.

It took all day, and all night, with Mac working non-stop till well into the next morning, but when he finally got it, when he finally popped his head out of the hole in the floor, face lit up with a smile, Jack was so relieved he felt a little dizzy.

"Its done?"

Mac nodded, eyes drooping as he leaned heavily against the edge of the floor hole.

Jack laughed, letting out a 'whoop!' in his excitement before he offered the kid a hand and hauled him up from the hole.

"I knew you could do it!"

Mac stumbled a little as Jack pulled him up, a tired laugh falling from his mouth. "Always late, worth the wait, right?"

Jack let go of his hand to thump his shoulders instead, eyes crinkling as he smiled in pride.

"You know it, man."

Despite how long they'd waited for them, their smiles didn't last long.

Mac's knees wobbled and he stumbled, eyes falling shut before he blinked them open again. He wavered on his feet, hands finding Jacks arms and holding on tight.

Jack's heart fell like a stone, to his stomach as his hands found Mac's waist and he watched that pale face closely.

"Mac? Buddy, you okay?"

Mac nodded, breaths huffing erratically from his parted lips before his hazy eyes rolled up into his head and he dropped.

Jack caught him, arms wrapping around the kid's waist and lowering them both to the floor, where he laid the blonde down.

Mac was nothing but dead weight, completely out of it as his chest rose and fell just a little too fast.

Jack placed two fingers at his throat, finding his pulse too fast and irregular. His own heart beat hard with panic, as he grabbed the photophone.

"Matty-"

Her voice came quick, though she sounded as tired as he was. "Is it disarmed?"

Jack looked back to the kid on the floor in front of him. "Yeah, the bombs disarmed but Matty, I'm gonna need a medic in here."

Matty's blood ran cold, as she looked to the two younger agents at her side, to see their faces as worried and scared as hers was.

She waved a hand to the waiting team of EMT's as she answered. "We're coming up now."

Riley, Bozer, and Charlie all ran up with Matty and the medics, racing into the house to find Mac on the floor with a worried Jack leaning over him.

Riley let out a gasp at the sight of him. "What happened?"

Jack reluctantly moved back to let the medics through, as Charlie helped him off the floor with an outstretched hand.

"He passed out as soon as he finished with disarming the bomb. He hasn't had anything to eat or drink since before yesterday morning."

Charlie watched as the medics looked the blonde over, shaking his head as he sighed. "Kid always did work too hard."

Admittedly, it wasn't totally Mac's fault, given that he'd had bigger problems to deal with besides missing a few meals, but they were all still worried and stayed until they knew Mac would be okay.

"Ugh...I'm-I'm fine." All heads turned to the slurred voice, Jack racing over and kneeling down beside the blonde.

Mac was already trying to get up, brushing the medic's hands away as he squinted his eyes open to the swirling ceiling above him.

Jack pressed against his shoulders until he was laying back down. Mac's hands came up to push the restraining hands away, but relaxed when his glassy eyes found Jacks frown.

"Stay down, Mac. I don't want to have to catch you again."

Mac groaned, lifting a hand to his head as it pounded. He really did feel like crap.

"Oh god, did I pass out?"

Jack nodded, grip loosening on Mac's shoulders till he was no longer holding him down, just...holding him. He had been worried, and couldn't help the physical contact to ground them both.

"Yep. Like a damn damsel, right into my arms. You can't let your blood sugar get that low, Mac. It's just not good for you."

The blonde peeked up at his partner from behind his hand, frowning at the tone.

"I was a little busy trying to disarm a bomb, Jack. I didn't have time to think about snacks."

Jack's expression was distinctly unimpressed. "Well, I did and you still wouldn't take anything. It might be your job to save everyone but it's my job to save you and I'm pretty good at it. So, next time I tell you to drink something or eat more than once a damn week, do me a favour and listen."

His voice softened at Mac's puppy eyes. "You did a good job, kid, just like you always do but if you wait till after the mission to take care of yourself, pretty soon you'll pass out before the jobs done. Use that big brain of yours and think for a bit okay? Or don't think at all and just let me take care of you."

Mac gave him a sheepish smile and nodded, eyes looking a little clearer although he was still as tired as ever.

"Okay. Thanks, Jack."

He gestured to his partner's hands still on his arms. "So, can I get up now?"

Matty stepped forward, her signature frown on her face. "Nuh uh, absolutely not. You're going to be checked over by nice gentlemen," she gestured to the waiting medics as Mac closed his eyes groaning. "And you'll be a model patient."

Mac tried to use the puppy eyes again, which only earnt him a raised eyebrow from his boss.

"But I'm fine! I just need to eat something and I'll be good to go. I'll go right to bed, I promise."

"I said no, Mac. Because not only are you underfed, dehydrated, and sleep deprived, your house still has a bomb under it. You aren't staying here until it's all cleaned up, and we have a new security system in place. Once you're fit to stand again without falling over, Jack will take you to his place for some sleep and water, and you aren't leaving bed till you've eaten your weight in pizza."

Jack aimed a smug smile at Mac as he pointed at their boss. "You heard your mother."

Mac laughed. Despite their rough first meeting, he was glad he had Jack to watch over him and a team that cared so much.