Just after the toy box multiball - probably within 5 seconds. Went to scoop for the extra ball, popped out of there, went right for the elevator drop target, hit it and the lights went out, but the flippers were still working until the version number screen popped up, then the flippers went dead too until the reboot completed. First time I've seen it happen.
So there was likely stacked video stuff for the end of toys, the extra ball stuff was started, probably the song mode was timing out or close to it, then the elevator was probably trying to show it is qualified for a lock.