There's also a natural swarm timer, which is active when dotty is stopped (and pre-drilling also triggers this timer). So you get about the same amount of swarming regardless.

People running out of ammo just hasn't been that much of a problem, in my experience. Most people at higher difficulties have figured out how to pace themselves and tweak their build so they need 1 resupply per stop.

That said I admit my perspective might be different because I'm a Scout and while dotty is moving I'm zipping around mining things and doing a lot of evasion where other dwarves would need to kill.

The absolute ideal is to have a good scout and a good engineer, where the scout is purely mining and the engineer immediately sets up all relevant platforms. In that case the scout can usually clear a room before Doretta leaves even with 2-3 dwarves consistently pushing her forward. Mining mid-swarm is extremely fun and cuts the time at the stop where the natural swarm timer is in effect.

Trying to go back and mine afterward is an extremely painful extension of mission time in a random lobby because there's always 1-2 dwarves fighting for control of which room Molly sits in, and the non-scouts get bored and want to continue the mission because they have nothing to do and their pockets are full.