How do I complete stage 2 level 4

I don't set a policemen, I let them walk to the door and build stairs to make them go back. The second one who ist not build a way through this block go back to the stairs as a miner and destroy the stairs

Let only one go over at first to have him build over the exit. He will return and then you can bash through the right side of the block. Once your stairs are built you ma.y want to send one or two more over the block in case basher misses. Dig through the stairs to exit

Let one lemming climb over then have him build a staircase over the exit door. On his way back build a staircase all the way up to the other side, while he's doing that have the lemmings on the other side build stairs back and forth to get to the top... Don't forget to build stairs to catch their fall so they don't go splat! Then use the digger or Roman to break through the stairs covering b the exit. It takes a while to aim everything perfect in the allotted time, but I pulled it off

Build a stair over the exit. The lemming reverses, dig through the wall, dig through stair when returned