This is about the third time in this thread someone has mentioned "locking yourself in." I say again, do not lock yourself in the cave. Lock the gate open - that is, lock the lock to the chain with the gate *not* locked so that no one can lock you in with that lock....I don't like the idea of it locking myself in, or even "pretending" to. If I need out of the cave, I want unfettered access, not stopping and screwing with some stupid gate. That's one reason I haven't dove beyond the gate at Vortex. On the other hand, if you're gonna mix open water divers like they do, there has to be something more than an "honor system" to keep people out of the cave.
The ideal way to dive the Vortex cave is to leave a guard at the gate while the caving team does its thing beyond the gate. We do this whenever possible. Be aware that the guard is deep too and this duty is usually a deco dive as well.
Rick