Hello all!
Some kind people pointed out a problem when playing with v3.3.2 or earlier. Apparently the BLOCKASPLAYER actor flag only works in v.3.7.2 or newer and causes the game to crash on load up. So until I figure out how to make this work for earlier versions, make sure to update your GZDoom.
Added some brightmaps (first time making them) so now the merc enemy has a shoulder lamp with dynamic light bound to the actor.