my point is you shouldn't simply blow one up in your face.

do you see people walking around in narrow corridors and hallways with their sniper rifles drawn? of course not. they have these things called pistols out that really do quite nicely in close range. it only takes 1 good shot to kill someone, and you have 6-8 depending on what you're using. i've ambushed people with pistols countless times. the other guy's usually focused on dancing around, spraying all over the place and not taking you as a threat.