His arms fold over his chest. No, those weapons aren't primed. Good chance he can dodge before there's an actual shot fired.

"First of all, you really don't know how many Autobots are here. Firing on their favorite mini isn't a good way of making the allies you're going to need. Secondly? I don't think you want to piss off Megatron this early in the game. Finally... I've already died once. How overprotective do you think Optimus is really going to be?"

Spoilers: Bee is only out and about because he can give the Prime the slip.