Tony can't promise that but Bruce needs desperately to believe him. Tony was his center point, no matter what, and he tried so hard to be one of those for Tony too. He wants to keep this two ways. They give and take from each other. He needs to be here and alive to keep that going. This isn't about you, this is about him.

He knows he is likely already infected. With how close he is to the virus and the people breathing on him, it's a countdown to when, not if. Bruce no longer has the Hulk to shield him. What he has to do is keep with it long enough to fix this. He does take a step back when Tony coughs, but not because of him breathing on him, but because he'll need to the space to get the air back into his lungs. Bruce's clinging to him doesn't help that.

"I would never make a different type of face again. That would permanently be my face." Bruce would lose his mind for sure. He needs that mind. He needs Tony Stark. He leaves for a moment just to get Tony that water and comes back, putting it in his hand. "I love you." He's said it a few times now, mostly because he is positive Tony doesn't hear it a lot, and also Bruce himself rarely gets to say it or express himself. But he does. "Spend some time talking to the others when they come in. You might be able to check in on each other if you're hallucinating and ground yourself."