Strategy
Mouse
Daring players can Air Jump through the air towards one wall and Wall Jump up into one of the holes. Otherwise, wait for a Shaman to build a bridge to a hole.
Shaman
Defeat the other Shaman and build a bridge. Simple and easy, but still watchout for some mice, as they can troll your bridge up and result in creating not more as super-long, tippy broken plank.
Another possible idea is for the shaman to ghost spirit the mice across, but this often ends in more than half of the mice dying.