He doesn't jump out of his skin, to his credit. A good three inches in the air, yeah, but not out of his skin.

But more importantly, he manages to jump quietly, because it's been a pretty nasty couple of days so far and even a motormouth like Sam can appreciate the value of panicking in silence when you've already had wildlife and other people try to kill you in ways ranging from fast and easy to slow and painful (and re: that latter, he's pretty sure if he runs into Wiress again after knocking her over that waterfall, she's going to try to make it even slower than she promised the first time, which is no good).

Deep breath. Collect himself. Don't give in to the impulse to yell at Wash because oh my God don't do that.

(The look on his face does a very good job of silently screaming "oh my God don't do that," though.)