Hey guys, i don't have any screenies yet dunno how to upload so post how to, untill then ill just tell you how.
When you go in the tunnel part where theres a ladder the wall when you come up comes out where u can sorta hide, run into that wall and you should get in!
Right click at the corner then run forward [Aiming down the tunnel to there base on the wall]
remember that its on the right wall not the left side when you get in crouch and you will see thru the grey walls or you can look down and shoot people comeing up the ladder :]
HAVE FUN!
And thank me if this helped :]
Found by
ME!,my noob account
GLITCHURS
LEGO
AND,PRESANTERS.