Also the concepts involved in quantum realities, which they mentioned, allow for these types of paradoxes. Since Pria came through the quantum wormhole prior to its destruction, that set off a new quantum timeline where the Orville was not destroyed. Shutting down the wormhole does not erase the past but only changes what happens going forward as their reality shifts from the old one to the new one. Yeah, its tough to grasp the concept that if they shut down the wormhole, how does Pria pass through it to effect the past. The simple answer is she came to the past from a different quantum reality, one which still exists and where the wormhole is still active.