any teenager with FPS experience knows how to take a corner. Saw that all the time in training. The advantages an AR-15 has over a hand gun is barrier defeating capability, effective range, and shock value.
A guy with a long arm is always going to better able to land shots at ranges over 30 feet, combine that with a 5.56 cracking as it passes you and you got a lot of shit you got to deal with. i would NEVER want to have to face down some guy with a semi auto rifle with nothing more than a hand gun even at contact range. at ranges over 20 or 30 yards? fuck that noise. want to see how a handgun vs rifle fight TENDS to go? read up on the 1986 FBI Miami shootout. cliffs notes: 2 guys took multiple handgun bullet hits from various cartridges and still managed to kill 2 agents, and wound another 5. the take away was that one of the suspects weapons, a mini-14, was absolutely devastating in the fight. Each agent hit by it was either killed, or so severely wounded as to not be a factor in the fight. meanwhile, the agents and the perps were able to fight on, and in the perps case, fight on EFFECTIVELY despite being hit by either shotgun pellets or handgun bullets. often multiple times.