When Mr. Collier dives into the bed of the pickup truck, 2 men put as many drums of sodium cyanide into the bed. No attempt is made to secure these drums in spite of the dirt roads, and the truck doesn't even have a tailgate.
A recently discovered stone age tribe would not be able to understand English as portrayed.
The team is told numerous times that no one is permitted to cross the bridge without permission yet the team crosses back and forth on the bridge at least three times and no one notices.