Guild Wars 2

During the event, if you’re not already inside the walls, you can get locked out, the doors will not open, preventing one from participating in the event. Also, if you’re inside the walls during the event, the doors will also not open, preventing exit.

This is on Dragonbrand server.

The Risen have literally broken their way in, so there IS a hole/broken gate you can get through. It just happens to be filled with hoardes of undead. All you need is a little stealth, and/or speed and/or luck.

You CAN also get in or out with careful or creative jumping. Jumping OUT (straight over the glowing fence) seems easier for me. To get IN, I usually go to the top left (Northwest) entrance and jump up on the nearby lamp post (or whatever it is) to get a little elevation to jump up and inside.