Yes it was complete speculation but having taught some guys bound for Egypt Air because there Dads were Captains there it would not surprise me if they got it wrong.
Ah, a short search on youtube brings up this!
Pretty clear cut if you ask me, clear instructions, and clear read backs. Twice in fact.
Looking at a JFK chart it would seem they entered the runway as the next instructions were right on 22R hold short of J.
The diagram on the youtube clip is I think not correct. Expect they entered at either G or H.