Remove the dig-build near the exit. That's not the core idea anyway, but a supplementary idea. The main idea is that you send the floater down, then back up, and down again. When you remove the dig-build at the exit, you can remove the digger, which is critical for my v13 backroute.
Alternatively, put one-ways on the wall at the exit. Then the dig-build becomes obvious, and you have sacrificed this extra idea again, to fix and focus on the main idea.
Bonus: When you trim the skillset, the level will allow fewer things that seem to work, but then fail for technical reasons. That was my main critique from my previous post.
