Would they have really "won" the negotiations?
When the authorities came in at the end and discovered a dead guard, would the governor have really honored his promises? Didn't Figueroa ask if all the guards were alive/unharmed? And Caputo assured her that they were (without knowing the truth, of course).
So it seems unlikely to me that the negotiations really would have gone the prisoners' way once the authorities discovered that a guard had been killed in the riot.