Untrusted off-world mercenaries held in the new brig, all of them now gone except one.
The Brig was built to hold off-world mercenaries the team couldn't trust. According to Zhang, none of them ever tried to escape: the building is well constructed to prevent it, and by the time they're inside they're all pretty resigned to their fate.
By the time Carl arrives an hour before the plan begins, the brig is empty of all prisoners save one — the one Carl specifically asked to leave alone. Carl isn't surprised, and understands immediately that this is the consequence of giving Li Na the second Ring Divine Suffering.
Captured off-world mercenaries, resigned to their fate by the time they reach their cells.
Untrusted captives whose disposal was the unspoken purpose of arming Li Na.