Honestly, Your last two sentences are what I noticed.

Someone could easily sneak behind, or use another forward distraction to grab that butt gun while that guy's hands are both occupied carrying other things.

He doesn't look prepared at all to actually protect anything. Given his size, he should put all the guns, his cookie (or whatever he bought), and his keys in a bag so he has at least one hand free to defend himself. He could do more damage hulk smashing than trying to hit something with a tiny projectile.