Riddick: One down... Three down. You see where I'm going with this?
Riddick: You're not afraid of the dark, are you?
Other mistake: The trip back on foot from the nodes for Johns was way too fast, and he likely would not have had enough ammo to handle the entire trip back. From Riddick's perspective, John's left, he cauterized his wounds with some explosive debris, fought several creatures and then ascended the hill continuing to fight creatures. By the time he hit the top of the hill, Johns had made the entire trip on foot, which was long by bike, had Dahl join him, locked in the node, and piloted the ship back to Riddick.
Answer: Santana's prisoner was played by R&B singer Keri Hilson. Being unshackled and molested by all those men was probably the reason why.