You are correct. There are people who could possibly do such a feat.
But do you really think this bozo trained that much?
Maybe, but color me really skeptical.
Trust me: it really isn’t that hard. What he did amounts to just pointing vaguely in the desired direction, pulling the trigger as fast as possible, and reloading when empty. He wasn’t trying to be particularly accurate. It doesn’t take much training, just basic familiarity with operation.
Being _accurate_ with each shot in that time, which he wasn’t, takes more deliberate practice, but still isn’t that hard.