Think about it...
That ship could have just left after the bomb was on the corvette. No other fighter patrols were coming in, because the one that came back was destroyed.
Did the frigate stay to mop up fighters?
Because I think that ship could have just left as soon as the team was on and all the covenant fighters were destroyed no?
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I don't think it could have been saved. Had it fled the battle because it delivered the bomb, the Corvette would have probably started a chase...which would draw attention and would bring the ship further away from the Carrier That would conflict with the goal of the mission, so I guess the Savannah was ordered to try and hold out as long as possible.