The big benefit of this power kicks in 'after actions resolve'.
If you Push or Mystics off of this SP, no hindering tokens would be placed and nothing else would happen, correct?
Also, if you would lose this power before your next turn, markers would be removed, yes?

METREON GAS VENTING: U.S.S. Enterprise-E can use Phasing/Teleport. When it does, after actions resolve you may place a hindering terrain markers in each square it moved through occupied by an opposing ship and roll one d6; on a result of 5-6, deal each ship occupying those squares 1 damage. Remove the markers at the beginning of your next turn.

If you lose the power, the markers go away.

I'm not sure what you mean by "nothing else would happen"

Correct. If you push to use Phasing/Teleport and Metreon Gas Venting is no longer showing, then you would not place any hindering markers and you wouldn't roll, because pushing happens as actions resolve and the markers are placed after actions resolve.

Also, as red king stated, if markers are placed and you lose the power, then the markers are removed.

Thanks.
I hadn't completely thought through the Mystics thing. It happens after a Phase, so Mystics would never be in play at that point.

Just thought I'd make certain I had the right idea here.