it may be that the remaining character's opposing moral viewpoints make it difficult for the players to create a compelling narrative around the PCs continuing to work together, which may require some party shakeup. But I think that's up to the players to decide.
A further complication in this respect concerns Leila Lo, the ladyfriend of Vincenzo, the PC owner of the group's starship. the research vessel
St Christopher. Leila Loa was formerly the owner of said vessel and a lead figure (and chief medical participant) in a bioweapons conspiracy that the PCs shut down. In the process of bringing the conspiracy to an end, by destroying its main base on the world of Olyx, the PCs had abandoned their original ship - the Type Y Yacht
Maybe <Not So> Lucky, which Vincenzo had won in a bet (part of the backstory that emerged from his PC creation process) - and taken possession of the St Christopher. In the denouement to those events, Vincenzo gambled with Leila for title to the St Christopher and won. She remained on board as sometime pilot, chief medical officer, and his romantic interest.
In game terms, Leila lives on Vincenzo's player's position sheet, together with his two main characters Vincenzo and Tony, and various other secondary characters including - until his untimely death by Alissa's grenade - Bobby "the robber". But as a secondary rather than primary character Leila lives in a grey zone between PC and NPC. A little like an AD&D-era henchman, I guess.
In that spirit, it recently turned out that Leila has not lost her taste for bioweapons experimentation. To quote again from the post quoted in the OP:
In the previous session, the St Christopher had survived an Alien attack while in jump space (the attack being the result of the experimentation of Leila Lo,
a space captain and surgeon and former owner of the St Christopher when it was part of a bioweapons conspiracy) before arriving at Novus.
It is currently established, as part of the outcome of those events, that another of these grey zone characters,
the one-time mercenary interrogator Mitch who hangs out with Xander and sits on the sheets of Xander and Roland's player, is in Leila's surgery. And it is presumed though not actually yet established that as part of Leila's ongoing experimentation Mitch has been implanted with alien spores that will transform her into an Alien or something similar.
The only character in the PCs' group who really cares about Bobby is his brother Johnny, who is employed by Vincenzo as a driver and bodyguard. But Johnny is himself a grey zone character and so unlikely to be an instigator of (eg) a revenge scenario against Alissa (as opposed to, say, a pawn in my GM's hands if Alissa does something that suggests an immediate revenge-type response from Johnny).
On the other hand, Xander is a primary PC, handy with a variety of melee and firearm attacks, and the only character with battle dress and a portable energy weapon (PGMP-13). If/when he works out that Leila is experimenting on Mitch, there is quite a degree of likelihood of some sort of party shake-up!
EDIT: In case it's not clear, I the GM was the participant who decided that Leila was experimenting with Aliens on board the St Christopher: (i) because otherwise what's the point of having Aliens in the game!; and (ii) to introduce a bit of action.