mnietek: So I played up the "rep sympathizer" path, got the reactor and went inside the moonbus. Now I have four characters standing around me (Clovis, Lucy, Dektora and Sadik). I know I'm supposed to talk to Clovis (and if I do, the game ends), the rest of the characters are "no the talking type". But I can, with a bit of luck and using the speciall ammo bought earlier, just shoot everybody. The problem is that if I do so I cannot progress anywhere. There is nothing to be done with the bodies, the background is not-interactable and there is no way to exit the moonbus.

PraetorianWolfie: Can you make sure that the twins are not sitting in the background? If so, you'll have to kill them too, even though they are harmlesss.

If not then, can you provide a save game for this, please?

mnietek: It seems the twins are probably somewhere _behind_ the background. They are not visible, the crosshair cursor changes to red when I aim at a particular piece of background. After shooting frantically every few pixels apart, I was able to shoot them indeed even though I didn't see them.
Thanks for the tip.

PraetorianWolfie: Glad that you got it working.
However, please attach a save game, if you have one available, so that we can debug the issue of the invisible twins (they should not be invisible).

mnietek: No problem. Uploaded it here
I played the game with restored content.

PraetorianWolfie: Thanks for the upload :)
From what I can tell launching the save from my PC the twins are visible (as visible as they were in the original) sitting onn the co-pilot seat in the background.

Unfortunately, they are always hard to notice because their idle movement is subtle and they are partially hidden by the seat. Also their hotspot is a bit bugged; I could try and improve that at least.