The RAW spell isn't specific on the destination on the home plane (obviously designed to be cast on random outsider whose fate doesn't interest the players in any way). It could be a random place, but then it would be randomly deadly (on an earth-like planet, you'd generally end up far in the sea... and the prime include outer space as well..). The intent of the spell is to be harmless (if you're native, you're taken to a safe demiplane for the duration of the spell), so at least it should send the PC back to somewhere safe-ish. Maybe... the place they entered the outer plane from (but it would be too easy to exact vengeance on the NPC). At this level, they should be able to get in touch with each other quickly (but not necessarily regroup quickly, which is not fun).
It's something the players might attempt, unless being told of the risk of ending up in an inappropriate location beforehand.