Plot hole: At the end of the film Mardukas reveals that he has been wearing a body belt packed with cash - "in the neighbourhood of three hundred thousand dollars" - ever since Jack detained him in New York. Are we to assume that Jack Walsh, an experienced, hard-bitten ex-police officer, now a bounty hunter who routinely chases down violent and armed bail absconders who would kill him without a second thought, didn't even perform a perfunctory search of Mardukas when he detained him? This man used to work for the Mafia! What if he was carrying a weapon? A body belt with three hundred one thousand dollar bills in it would be uncovered by even the most casual pat down.
Plot hole: When Kalgan is torturing Lea, he says that he wants her father's countermeasures in case of emergency. But when she is rescued and finds out MacPhearson is a traitor who is working for Kalgan, Captain Devers is worried because MacPhearson knows all of the ship's countermeasures. If MacPhearson knows the countermeasures, then Kalgon does too, so there is no reason to bring it up while he is torturing Lea.