I completely understand that, but my counter point would be the Hulk was exactly where he wanted to be. He choose to guide his fall there and there wasn't likely any reason for him to leave that area. With no additional stimuli - he should return to the unconscious Banner. Is anything I'm saying here entirely unreasonable?
Whatever effect the scepter had on the Hulk had worn off - either by the time the jet exploded on him (likely) or the time he hits the ground (less likely). At that point the Hulk would no-longer have any reason to remain the Hulk (calming down and reverting to an unconscious Banner - which is consistent with every depiction I can remember from the two films this Hulk has appeared in).
It seems consistent with every other depiction of the transformation / de-transformation.