We should have known that all Minnesota players have the mental speed and capacity of top flight physics researchers to calculate all that.
Not at all. If the puck would bounce off the way people expect, it wouldn't help them any more than it would help The Blues. The unpredictability of its bounces off the stantions is all they needed to get loose pucks in the offensive zone fore their forecheck, given that unpredictable bounces would make it harder for The Blues' defenders to grab the puck earlier and have time to control it without pressure, and get it up ice.
On the forecheck, the defending team is back, closer to the dumped-in puck, and most often wins the race to it. Strategy on dump-ins on the forecheck is mainly to skate in quickly and get a body on the defender who has first gotten to the puck, before he can pass it to a teammate. Forecheckers rarely win the race to the puck when it is dumped in. Most often, the defender arrives before, and the forechecker arrives a split second or a whole second later, before the former can make a play.
By planning to, and hitting the stantion, and sending the rebound (seemingly) randomly out into the middle of the zone, The Blues have no more idea where it will go than The Wild. The Wild skating into the zone, separated to get as much coverage, have , at least, as much chance of grabbing the loose puck (if not even more, as they are covering all the different areas of the zone as they can, whereas, The Blues, not guessing the puck will hit the stantion, are skating towards where the puck should (but will not) go, when it just hits the glass).