1. go to the top left of escalation at the pile of rocks against the broken wall at the left side when facing the mansion.
2. face the wall and walk side ways up against the rocks agaonst the wall ( you cannot munt on the wall).
3. keep doing this until your guy starts to shake then jup to the right mount against the wall instantly( or you will teleport back without mounting)
4.after mounting against the small wall you will teleport back still mounted.
5. now you just push forward and A with your camera facing the wall then you will end up in the room. * warning if done wrong you will become stuck on the middl floors lesdge if this happens ask a freind to stand under you and simply walk off).
6. after you are in the room you simply walk through the black wall infront of you and you will be out of the map!! ( if walk throught the wall to your left you will be stuck in rocks and p.s. when youn leave the room you cannot go back in.)

if you would be willing to video this the finer of this glitch was ICP RAMBO AND ICP HEADSHOT we are willing to help.