I thought at first they might be out-takes. You know, those amusing moments when an actor muffs his lines or accidentally trips, there's a mis-cue, or a prop malfunctions. LAW's press conference set me straight. This was just a bunch of kids playing funeral.
I've never seen or heard of an out-take, though, that caused the extras to run in terror.
I've never known of an innocent game kids were playing that caused the grown-ups to run in terror.
Except for the lady who thought the five year olds yelling "Kapow" was German 88s. (Confession: I made her up).