What if you had an area of map that wasn't enter-able in the center of map, this area would clear on a timer making for an escape also based on a timer.
Think galactic gate to another game/map.
You could edit this setting with a player requested gate/unlock for the gate.
As in FPS since first tried in player unknowns arma mod it has spiraled out of control in popularity and could bring an ending to matches within sensible time frame.
Just an idea I thought maybe of more use to a large scaled map modding community than a game company?
Oh and hi everyone as first post.
Have you looked into the "Claustrophobia" game mode?
It's not exactly the same thing but it has the same vibe as what you're suggesting.