Revealing mistake: In the scene where Sarah crashes into the agent's buggy, you see they have been replaced with dummies. When the car first hits, you see one of the dummies fall out, but they are both seated in the next shot. Also you see that it is not Sarah driving but a man. (00:36:50)Melissa Jane Swift
Other mistake: Michael goes to Fox River in April. Maricruz gets pregnant in the same month. In mid-June, when Michael get arrested in Panama, she's still pregnant. That's 2 months. He was in there for about 2 weeks, due to his deal with the company. Therefore, he would have escaped Sona at the end of June or the start of July. The start of Season 4 is set 3 weeks after the escape from Sona, so Maricruz should be 3 months pregnant, but gives birth at the start of season 4, meaning that the baby is 6 months early but looks very healthy.
Plot hole: They exchange Scylla for the life of the general's daughter. If they counted on him valuing his daughter over Scylla, which he did, they wouldn't have had to steal the cards or break into the vault in the first place. Just kidnap the daughter like they did, tell the general to gather the cardholders and hand over the cards, give them Scylla and let them out.