Before the movie's even started properly. Sam takes a long, dramatic walk to the debriefing chamber, escorted by guards and accompanied by tense music every step of the way...including the part where they have to struggle with a malfunctioning gate and then get lost in the corridors and have to backtrack. The music never changes.
When Sam first arrives at the Espada Ardiente camp, one of the farmer-soldiers in the foreground is seen maintaining a muzzle-loading weapon. While Beatriz is trying to convince Sam that they're not as poorly-armed as they seem.
Sam tumbles out of the jungle after being "kidnapped" — one of the soldiers in the scouting party radios back to base with, "(subtitled) We found the white guy!"
A little later, Sam tries to stall for time finding the "terrorists" by pretending to get directions confused on the map.
The entire bomb-building scene, where Sam has to enlist a terrified doctor with nothing resembling military experience at all to make a bomb out of equipment from around the clinic.
Sam: Yeah, we're making a bomb, so do the exact opposite of what it says on the warning label.
And then later on, when the doctor proves to be scarily good at making improvised explosives.