[EnerPrime]

That whole Shinken/Gosei battle part in that episode is actualy an explanation of the Gokaiger's cameo in the Gosei/Shinken movie. There they showed up and used DekaRanger to Go-Onger's Red keys. I think the time travel was a neat way to take a cameo that previously made no sense (seeing as the movie has to be before the Legend War, therefore the Ranger keys shoudn't exist yet) and make it work. It's also explains why a certain prominent extra hero never got a Ranger Key. It' pretty much an episode dedicated to a couple of continuity fixes.