The Dimensional Breach is an encounter centered around a gravitational anomaly. Upon locating the anomaly, it is found that a Mirror Dimension can be accessed and players find themselves with mirrored versions of themselves with the same gear and same objective. Their objective is to defend and closes this breach from waves of creatures come in from the other side.
The thought is that as creatures spill into either dimension (using a Binary die or coin) that players can take an action with both versions of their character. Additionally, if one side gets overloaded with creatures, players can jump back and forth between dimensions with a HARD CON roll, but if the breach closes and a player is in the wrong dimension, that version is utterly destroyed.