Plot hole: Dirk thinks that Kazim's chopper must only have 20-30 minutes of fuel left because he didn't see any extra fuel tanks on it. First of all there's no way Dirk could know that just by looking, since he doesn't know how long Kazim was flying. Secondly Kazim had been flying around for several hours looking for the gang, so either he would have had to go refuel at some point or he did have extra fuel tanks.
Factual error: Dirk is fighting on top of the solar plant with the guy who attacked Eva at the start of the film. Dirk shot him in the hand with a spear gun. It doesn't matter how tough the guy, is he would not be able to hit Dirk with that hand without being in excruciating pain.
Continuity mistake: At the end of the film the waiter/agent serves up a glass of bottled water and gets in the lift, once in there we see him remove his bow tie but when we see him go down in the lift he's wearing the bow tie.
Other mistake: After Dirk, Al, and Eva jump from the camels to the train the camels are seen practically huddled together when noticed by the guard even though each camel traveled further than the last one.
Answer: So they will not discover the poisonining that is going on.