The answer to that is in the media

. To get a enemy to go through segment walls, change the appear script to appearnogravity.fpi and change the main script out for one that will have him search the player out like this one:
;Artificial Intelligence Script
;Header
desc =
;Triggers
:state=0,plrcannotbeseen:rotatetoplr,movefore=1,animate=2
:state=0,plrcanbeseen,plrdistwithin=50:state=1
:state=1,plrdistfurther=51:state=0
:state=1:animate=6,plraddhealth=-10
;End of Script
This effect can be seen with the least known ww2 media character, The Skull.
WARNING: there is a small chance that the character will get hung up on a wall.
Have Fun