In Ivan Reitman's Ghostbusters, the team are able to dispatch Gozer back through the interdimensional gate through the use of 'total protonic reversal'- after crossing the proton streams they were able to reverse the flow of the entities and their associated PKE ("The door swings both ways").
In Jason's Ghostbusters - Afterlife the expanded gang appeared to successfully trap Gozer (and once again all associated PKE) in the elaborate set up on the Spengler farm.
What happened after that? With Gozer et. al. now 'trapped', did they end up in a storage facility and if so did this have anything to do with the ominous closing shot of the protection grids control and access panel at the Manhattan firehouse, which was shown with a red caution light having been activated? I was under the impression that the premises had not been used until Winston was able to recover the property in the final post credit sting.