My (possibly wrong) interpretation of what's going on here:
- The slider walks of the edge, begins dehoisting.
- The digger clears a pixel of terrain.
- After dehoisting, the slider no longer has terrain, so it falls.
Observed result:
- The slider begins falling and lands on the edge of the digger pit.
Desired behavior:
- The slider should either keep sliding, or fall off the wall into whatever's below the wall (appears to be a death pit in the example). Ideally, this result should be consistent and not dependent on the exact timing with which the slider reaches the edge; I have a slight preference towards always allow the slide in this situation. If a digger can remove the terrain from the slider when timed correctly, however, then it should at least fall away from the wall and not into it. Sure, maybe internally the lemming is 1px into the wall, but the player shouldn't need to worry about this implementation detail.