THIS IS NOT THE NORMAL GLITCH near site B in snd. This is near site A.
So on bravo you spawn take a left climb up ladder.
Now crouch and knife at left side of vent.
Once you can see inside then slowly tap foward and jump.
If you've done it right your inside vent.
Pictures:
(As far as I know I'm the first to find this [well and post it atleast] if I'm wrong please don't flame)
(PLEASE DO NOT SHARE MASSIVELY --OR ELSE NEXON WILL PATCH )