In The Flash season 2 finale, "The Race of His Life", after
Zoom kidnaps Joe
we are shown a scene on Earth-2, where we can see that
Zoom is still holding the masked man prisoner in his cell.
Flash later contacts Zoom and tells him
that he'll agree to the race on the condition that he brings Joe back to Earth-1 with him.
Later, Zoom agrees to this condition and appears
with Joe, but not with the masked man, who is presumably still locked up in his cell.
Yet after the climax of the episode,
Harry and Cisco are suddenly shown removing the masked man's mask, revealing him to be the "real" Jay Garrick of Earth-3, and also Barry's father's doppleganger.
When did this happen? At what point did
Earth-3 Jay crossover from Earth-2 to Earth-1? Did Zoom bring him to Earth-1 with him at the same time he brought Joe (and if so, why would he do that, when it wasn't a condition Barry imposed)? Did the heroes go to Earth-2 to go get Earth-3 Jay then come back to Earth-1 (and if so, then why did Harry and Cisco not take his mask off then, rather than waiting until they got back)?