Wear, tear, and rust.

"I'm not asking to peek in on an actual exam, dude; come on," she says, rolling her eyes. "I'm still thinking intervention and prevention here. Giving the medical staff an overview of signs and symptoms to look out for, and working out steps to take if this thing breaks loose on the Barge - that's what I want to be there for. If you want check-ups, that's a good idea too, but that's your business."