I don't think they really waited, so much as didn't arrive till everyone was already gone. I mean, how long does it take between the time the clerk knows what's going on, and the time the thieves are out the door?
Oh. I misread it, I guess.
If they are not near, I guess it would take a while. The clerk should have called the fire department. The guys in my neighbor hood get here in two to three minutes.