What are some glitches in left 4 dead

First of all insted of alerting the horde on the one when you have to move the dumpster insted find a garage dooor near it. have a team mate cover you. crouch down and start shooting at the bottem right corner with a pistol. BE PATIENT! JUST CONTINUE TO SHOOT DON'T STOP! soon it should open if not they may have removed the glitch I'm not sure cause i haven't played for a while. once i start again I'll be back to write more.\


They removed, you can't do anything but just do the automatic glitch