two sephiroths

[Storm]

Phoenix, I like your idea that Cloud released Jenova from captivity in Hojo's lab. It explains why Cloud's cell was open afterwards. It wouldn't make any sense if Seph or Jenova opened the cell.

Remember right before the group gets kidnapped, Cloud looks through the window of that container that contains Jenova and he starts freaking out. It's possible the Jenova was communicating with Cloud subconciously and Cloud eventually released her from captivity.

However, how did Cloud get out of the cell in the first place? I don't even think the Turks are silly enough to have forgotten to have locked the cell.