Well, I've been trying to keep it moving as fast as possible, though that hasn't worked out 100% of the time as players have family or school commitments. Basically what's happened thus far is that the Inquisition sent the cell to a planet called Famine in the Calixis sector with a curious history (invented by me) to examine some artifacts captured by the local Adeptus Arbites that have a blasphemous resemblance to the local Imperial cult and its local saint. The characters did some snooping and determined that these items have a link to a criminal gang (just what they don't know). They are currently in the midst of a firefight. Oh yeah, they almost tried to eat each other.
The characters are an Arbitrator, Psyker, Tech-Priest and Guardswoman. The Arbitrator's player vanished mysteriously a couple of weeks ago and so I have been NPCing him, but since he's been serving as de facto cell leader this is a little too close to the GM leading around the players. Thus, he has just given his life for Empra, laid waste by a shotgun blast. I need someone to take his place.
The rationale for drawing another character in would be that the remaining Acolytes request an additional person from the local Arbites to supply knowledge/abilities they lack. Basically, these characters -- two freaky Void Borns and a rather, um, direct Guardswoman with no people skills -- have no Interaction skills to speak of, really stand out in a crowd, and we need somebody to make up the lack. The character would have to be from the planet (an Imperial Worlder), and probably either an Arbitrator, a Cleric (for useful religious knowledge), or Scum (links to criminal world). A case could be made for an Adept, but there are already two scholar types. The character wouldn't be a full-fledged member of the Inquisition, at least at this point, but being a local would have a lot of knowledge the others do not possess.
Personally I like Clerics, but nobody else seems to.
Please let me know if you're interested!