Lifeboats? Surely you mean deathboats?
Surely everything about this vessel is lethal...
When you consider that Harrison has already referred to the Vengeance as having minimal crew in clips, high capacity boats wouldn't seem likely to be hiding behind those big doors. If you're bailing out into a tactical environment that this dreadnought hasn't survived, you probably want to come out swinging in something gunned-up, armoured and running a worked propulsion system. Deathboat sounds about right to me.
I also don't think there's any doubt that it is in fact the Vengeance we see plowing into San Francisco Bay. I wonder if it will be depicted as fully submerging in what I think is only 300 or so feet of water at the deepest. That would be right in there with the 78 deck 1701A we got foisted on us in ST:V to amp up Spock's rocket boot ride.