Every tile you stand on lights up and drops away a second later. The floor is spent by the people standing on it, so being last isn't about running fast — it's about spending it slower than everyone else.
Fall through and you land on the floor below. There are five. Fall past the last one and you're out. The winner is whoever is still up there.
Shift is a dive. It's a committed lunge you can't steer out of: land it on somebody and you bounce off them and they go flying, miss it and you hit the deck and spend a second getting up. Shove somebody over a hole and they're gone.