The groan from the other at least helpfully confirms he's okay, more or less. Horrible puns aside, Donnie's relieved that Leo's there. He is not going to think about how much worse it could have been, let alone what might've happened if Leo hadn't come to find him when he did.

...so he fails in not thinking about it, but at least the present outcome is more than enough to focus on. It's cold and wet but he's just trying to catch his breath.

"Okay... Maybe scouting sewers... during a storm...not... the best idea."