Maybe I'm just being blind, but I can't find the answer to what seems to me an obvious question...
minor plot point spoiler:
After being freed, what does Tomasz do after telling the PCs about joining the Cult? I assume he doesn't join the party, but that might actually make sense...
My most recent party left him in the care of the PFS contact (I forgot his name, no scenario in front of me) so that they could deal with him after the main mission.