When you're on the part of the map that have the lightning striking you, and you get stuck in the enviroment, you may be stuck with no way out. You get stuck in combat, but you heal up so you won't die. You can't use waypoint since you're in combat, and trying to use /stuck will only tell you to use a waypoint.
I had to log out, log in and quickly try to find a waypoint to port to (or port to home instance or whatever) before being struck by lightning again. There may be other ways around this, but this is something you need to look up.