He wonders if he should say something, but decides better of it. Best to let Kira handle himself.

And then he hears the gunshots and decides, yep, he would not have been able to handle whatever crisis he’s having.
He should probably just leave, especially if Kira has a gun on him, but he stays rooted in place. The possibility of more information outweighs the risks of obtaining it.

And if he can get one over on Shido…
He’ll just have to be careful not to piss kira off enough to get shot.

Eventually Kira returns, acting like whatever happened in the restroom didn’t, and decides not to press.
He’s getting the impression that Kira might firmly be in the ‘too many loops’ part of a time loop story… which is a bit troubling to consider.

So instead he just shakes his head.
“We all have our moments” is what he responds with, because frankly, he isn’t immune to rash violence as a form of coping.
…so unless Kira volunteers the information he just won’t ask for the time being.