I explain all things.
The Video is Port and it's a Super Jump glitch.
First Screenie (where I'm dead)
Go near the Ramp and someone push you,and you get in.
Second Screenie(with the UZI)
Go GR Base,or BL,and go near the door.Get someone to push you and enter.There is a bit of ground and you stand on it.If you go near the train you will die.