I've of course covered the Power Pack issue a couple of posts ago. Somewhat facetiously, but at the core of it was a serious point: this is atypically dark stuff. Power Pack crossed over with this because of the Simonson connection - it looks like we cross over into Thor for that same reason, rather than there being any solid story logic.
In these issues X-Factor search and rescue for survivors, find quite a few (in a number of batches), and take them home. The worst thing that happens, though, is poor Angel, who is separated from the group, pinned to a wall by his wings, and severely injured. This will have Consequences in subsequent issues, and is probably the third most significant character nobbling we've seen at this point (after killing Jean and depowering Storm). It's the issue where you can tell that Simonson has set aside Layton's initial set-up of X-Factor: a rather slavish recreation of the X-Men before Roy Thomas, and made it its own thing.
What else have we got? Well, X-Factor properly meet the Morlocks, finally. This has been long coming: the street book and the sewer mutants clearly belong in the same kind of universe (and they make a lot more sense here than randomly popping up in Westchester all the time). Contrasts can be drawn between the different groups stances (there are two identifable groups of Morlocks here with different positions) on mutant integration, and comment is made on whether X-Factor's shell game might not be counter-productive (a clue: yes). These surviving Morlocks are more prominent than ever: what didn't kill them made them more interesting.