Duke3D: Sprites can push you out of bounds into invalid sectors, causing instant death
This is one of those issues that started with the great clipping overhaul (r7428, d060ca95) and I expect it to not have an easy solution.
I noticed a while ago that enemies were capable of pushing the player out of bounds into invalid sectors if the player happened to walk into them at the wrong angle. This of course would cause instant death by cursectnum == -1.
The problem here was that I didn't have a good way to reproduce the problem, but I think I now have a testcase to check this behavior. The following map section is from map 3 of Life's a Beach: splashy_clipping02.map
By walking into the wall-aligned pigcop or battlelord sprite from the side, it is very easy to get crushed or stuck inside the sprite with no way out. Prior to d060ca95, this did not pose a problem, and the player never got crushed or stuck by walking at these sprites from any angle.