Alright me an dk173 found a cool glitch in cold seed. It's not too amazing but it's still something and it's quite difficult.
Alright here it is:
First stand about this far away from the wall (see picture). Aim your knife at the corner of the wall and run, nothing more.
Once you get in you'll see like a grayish brownish wall, stay against that and move forward a little. Don't move past where the wall ends or you'll fall off.
Anyways when you get in you can kill somepeople walking around the map.
You can still be killed however but the people have to run all the way back to the spawn point and yea.
Anyways enjoy :P