Switching Between MBB

Hello -- I've just finished up a summer internship at one of the MBB firms and gotten a return. One major issue I have is that the geography isn't where I want to be. I don't have some compelling SO/Family reason to move -- I want to be in a different geography simply because I love the region and think the industry mix is better over there. It's also important to note that I have 0 intent on being a career consultant so I'm pretty short-term focused on this.

And so the only path into the geography I want seems to be to switch to a competitor. The issue is that I can't just sit around on a return offer for 3 months and wait until the normal recruiting process happens for these companies. They'll start asking questions and it'll burn bridges a lot worse to stall it out and then jump ship in November. So I was wondering if there was some accelerated process that the companies use? I didn't get into the final round of the other two firms last year, but since I've essentially been 3rd party vetted/validated by another peer firm already, I wasn't sure that would play in my favor for having a better interview situation.

One other question I did want to ask is whether there's actually any cultural difference between how hard firms work you. It wouldn't play a huge role in my thinking process since so much of it is variable between different engagements, but I haven't really been able to see whether there is much of a verdict in this regard. Some say McKinsey generally works people harder than Bain/BCG, but I wasn't sure if that's more recruiting propaganda than anything else.