Probably a bad example about the bus, no I’d probably stay silent (and do). But if I saw something highly dangerous I would be more willing to step in.

I’m sure everyone reading my comment in their head is imagining something different. I was imagining some one being assaulted, and wouldn’t have drawn a weapon - just spoke up.

Frankly, I don’t think pulling a gun in a crowded place would almost ever be a good idea. Unless there was already an active shooter and even then, retreat if possible.