[@Sep]
I'd consider getting the Replicators moving so we have an immediate problem that needs solving-- beyond just making sure they don't get out or seeing if our anti-Replicator weapon will work.

Which, all things considered, it probably won't.

Depending on how powerful the fleet's lasers are, they can only core through so much of the city's layers before hitting a depth they can't penetrate. Especially if you factor in diffusion as the projectiles travel and whatnot. Replicators could start moving out of the quarantine that way. You could also have there be a ship or civilian transport that someone missed or hid, because realistically no one's going to take out every mode of transportation in so short a timeframe, to push all of us into going to a certain area.

To expand on that last idea, maybe a gang of smugglers or even Hutts are down in the lower levels with a ship of their own or something. Naturally, being averse to the law they wouldn't just hand it over, and a crime lord's gotta have a plan b in case things start going to shit anyhow. That could lead to a quest for the crewed ships to go deal with them before the Replicators do, and possibly even an encounter with Six (iirc) too depending on how you want to play it.