ZDoom

I was not sure is it my fault or gzdoom. I found solution for all such bugs, but after I cant handle crouching I thought that it probably something wrong in gzdoom.

If you do hacks like this, make sure you actually understand all the ramifications and reset the PlayerInfo's variables accordingly.

Load attached file and start new game.
After spawning type into console "summon dio". It summon dummy player pawn.
Mdk it. Nothing happens, besides death of dummy player pawn.

Repeat last steps but instead of mdk it press use on, it change player to dummy player pawn.
Now mdk original player pawn. It dies, but puppet, and player, die too.
You can use weapons instead of mdk, result would be the same, puppet player pawn would damage original after swapping player pawns.

Repeat last step again, but instead of mdk, again press use, but now on on original player pawn to complete "wheel of sansara" and return back original player pawn actor.
Now again mdk/shoot puppet. It kill/hurt it and also player.