Deliberate mistake: Kristin would not be physically able to hold Fabrizio from falling over the ledge using only one hand/arm (or even both). (01:30:22)
Deliberate mistake: Concerning the literal "bag drop" off the subway car: The ransom money bag falls from the train directly into the waiting hands of the bad guy, after it falls very arbitrarily from Denzel's hands, after the train is brought very arbitrarily to a screeching halt by another bad guy very arbitrarily hitting the emergency stop. This was sheer fantasy that could never happen in real life even if the thousand unknowns were known. Bigger than a simple plot hole - this was a deliberate mistake.