Did he really just remind him to take food and water? That Hatter could manage to remember. The way the people here just passed out food, it wouldn't be an issue. Just take everything to go for a couple of days and he'd have plenty without it looking too suspicious. So that he just laughed off with a shrug.
He did notice the scalpel. And he didn't really want to take it. The knife Hatter had in mind had been of more the hunting variety. Or self-defense, which was much more his speed than doctoring injuries. He wasn't really worried about not being able to do it. He just wasn't used to anyone having to depend on him so much. Or having to depend on anyone else, as he supposed there was always the chance that he'd be the injured one and Alice would have to take charge. So he looked down, knowing without a doubt that Simon had intentionally pushed that one away from the other instruments on the table. And he took a deep breath and slipped it into he bag, no questions asked. He'd return it when he came back, though when that happened, he planned to take Simon and his sister along with them. As well as anyone else he could manage. He could ride out the end of the world just fine without these people, thanks.
"I really can't thank you enough for this," he said, the words a bit stilted considering Hatter also wasn't used to having to be grateful. Nice, sure, polite, if he had to, but not grateful. "Me...I don't care so much. I've been through most everything, there's not much they can throw at me out there. But my girlfriend insists on coming along. She's tough, don't get me wrong, but..." He shook his head, then gave a little lopsided grin. "Doesn't mean I want anything happening to her."