thats a good one melbourne! karma for you:) I'm glad to see that noone posted a new quiz before this one is solved,
otherwise it would be confusing.
I think i got the answer, considering I did not set it up, I can answer it too

Well, you call another person to come and cross the bridge. As it is impossible to enter it without a pass, this person has got a pass.
You meet each other before the guards come out and check the bridge. This person gives you the pass, and you can go off the bridge
to freedome since you got the pass to leave it. Considering the fact that everyone who gets caught without a pass,
will get set back to where
he comes from, the person who gave you the pass gets to freedom as well since he comes from there.
Thats my theory, but I dont know if it is allowed to call another person to enter the bridge. If not, you could ask a random visitor, or steal it
from them..? I hope its right, if not, just let us know melbourne ;)