This is what we call, in technical terms, "Burning the Shit out of Your Foot with a Hot Piece of Steel".
How fast can a shoe and sock come off? I'm not sure, I wasn't running the stopwatch. But it was fast.
Lesson to learn here: Don't drop tiny pieces of 2,000 degree steel down your shoe. Whomever told you that was fun was pulling your. . . leg.