When I lived in Chicago and followed the Blackhawks (which I still do, from afar), there was no such animal as a “shoot out” (on the playing field, anyway). I asked a lady friend with whom I run if she knows what it means. She said Yes, but then proceeded to give me answers that were obviously wrong. (Why do some people say they know something when they don’t have the foggiest notion of the “thing.” Anyway, that’s just a side rant.
My guess, from the sports articles I’ve read, is that after a game is tied in regulation time, the teams play one o.t. period with 4 players each, instead of 5. (Is the ot period of the same duration as the others?) Then, if it is still tied, each team takes alternating turns shooting the puck in a net guarded only by the goalie. If it’s still tied (say 4-4), then I don’t know what happens.