how do u kill sim1 thats in a wall?
Go into the wall and get him. You can also capture all the CPs to end a level without killing everyone.
so u just walk up to the wall and u get through it?
No, see
http://www.lucasforums.com/showthread.php?t=150341)
There are glitches in the maps, where two walls might not meet correctly. If there is enough space between them, you can move through and into the wall. Sometimes it kills you moving into a wall. They are normally hard to spot and sometimes you can't even see them.