The question catches him off guard, enough that Vanitas' expression narrows— though he immediately regrets it. The dull, uncomfortable throb in his head swells with the squinting of his eyes, and in the same moment feels his stomach turn over. He's had two bites of sausage and the third was almost a full mouthful, but maybe it's too ambitious. It reminds Vanitas too much of that first time, when his head and stomach ached, when he guzzled the water and it all came back up immediately.

Only now he knows Bruce isn't trying to poison him, the way he thought Gene was.

"Of course I use it. What kind of stupid question is that?" He bites, a little more caustic now just because of his own discomfort. Vanitas puts the fork back down, defeated for the moment by the texture and the discomfort in his stomach. He still keeps feeling it rise up in his throat, like he wants to bring up everything he had the night before. Bracing one hand on the counter, he puts his other one on his bare belly and exhales in a single, long hiss.

It's the sort of self soothing thing he's used before, when the pain became this sort of full-body thing he couldn't shake off. He shoots Bruce a sidelong look from under his lashes, indicating he's actually still waiting for an answer to what may have sounded like a rhetorical question, before closing his eyes to try and stop the world from spinning.