Okay, so - the tech to get us home probably exists here already, in the threshold gates. We can't really test that without clearing up two complications first. One's getting the navigational data to send everyone to the right place instead of just another alternate dimension.

Second is quantum tethers. So, by coming here, we seem to have gotten tied to this universe, strongly enough to override the "pull" our own dimensions ought to have on us. Figuring out how to unstick that is going to have to happen to get us out of here.