This map appears to simply be a floor with a large, dynamic wooden block on it, but there is actually a large, fake floor under the block.

Mouse Edit

Ideally, mice would wall jump up the block, run over to the other side, get cheese, wall jump back up, and go to the hole.
However, this rarely ever happens, so you should simply wall jump all the way up and wait for the block to be moved. Note that the fake floor means that it is nearly impossible to push the block all the way without the shaman's help.
Being on top pretty much guarentees a free ride to the cheese. After that, simply wait for the shaman to build a bridge. Do not attempt to air jump over the fake floor as it is too large.

Note: If you're not able to wall jump, simply run up to the block and hold and (or W and D) simultaneously. The tilt of the wooden block allows you to wall jump using this technique, but it only works if many mice are wall jumping on the block, pushing it to the right.

Shaman Edit

The shaman should attempt to get rid of the block altogether. The best way to do this without killing mice is to first warn the mice that there is a fake floor. Then, simply spam transparent cannonballs headed towards the right, hitting the block.
The sheer enormity of the block prevents it from falling into the fake floor, so don't worry if it starts tipping.
Get rid of it by pushing it off the edge, and build a bridge over the fake floor.

If you're in a room where most people can wall jump, it is recommended to just red plank anchor the block steady.

If the block is already pushed away, all that's required to complete this is a simple bridge covering the pit. You can use Runes to see exactly where the pit starts and ends if you so desire.