What are you even...

This episode was just an aside-- a treat to the audience that the 2012 detectives aren't privy to. There's really not any reason to think e05 won't pick up right where e03 left off, after all this would presumably be the point in which the truth and the texas mission cover-up converge.

edit: I could be wrong here, obviously, but I don't get why you're so sure the plot is heading in some wildly different direction. It's far more likely that this is just another facet of an awesome non-linear narrative.