I think it could have, they coulda taken hostages and flown to their mother ship for more technology, maybe it was the cap nip getting them high?
They couldn't have have just flown there willy nilly. They needed the fluid to fuel the ship to get to the mothership. Not just that, but only Christopher and his son were intelligent enough to collect the fuel and pilot the ship.
A take over was highly unlikely. There were more prawns in the area then guards. However, one guard could kill several prawns. Not to mention that when prawns decide to get hostile, they're completely ****ed. They're only alive because we ferried them off their ship and sheltered them. Now the entire force of humanity will clamp down on them even harder, if not killing all of them while humans crush the resistance.