Can you "use up" a Security Station?

[bbq]

Lets say you have a ship with one Security Station V (220 anti-personnel) on it. First, in turn based combat you get boarded by a ship that uses two Boarding Parties V (200 personnel). Naturally you successfully defended against the boarders. What happens if a second ship then Boards you with one Boarding Party V (100 personnel)?

Do you win because the odds are STILL 220 to 100, or do you lose because you only have 20 "remaining"?

Thanks much.