The merc's generator is shown to be located a good way down the slope from the entrance to the cave, since Mac has to rip the extension cord out of the mossy leaves for quite a distance to find where it leads to, and it takes Mac and Pete a considerable time to reach the cave entrance. Yet when the mercs arrive and start the generator, the cave is shown to be just a few yards away, just to the left of their position, and clearly visible.
One second MacGyver is helping Pete after he slid down a rope line from a helicopter high above them and signaling the chopper pilot he can leave. Then the next second, the helicopter is seen moving off, but there is no rope line leading from it to them.
Pete and MacGyver walk into the cave, shinning their flashlights ahead, but their shadows are cast behind them up above on the cave ceiling, which could not come from inside the cave but rather filming lights.
When the seaplane first lands and the passenger got out to anchor the plane, the rocks move like they are floating.
The cave is obviously a set, and the large boulders move as if they weigh next to nothing when Pete jumps on them.
When Macgyver and Pete reach the downed plane Mac informs Pete they have no way to radio for help. This seems rather illogical for a few reasons. One, how did MacGyver radio for help when the participant broke his leg which is seen earlier, and two, if something does go wrong during the exercise, someone should be carrying a radio for help, especially in cases of emergency.
When Pete and Mac are hiding in the cave, they practically yell at each other, but Crandell , who was standing nearby, inexplicably doesn't hear them. Then later when Mac throws the grappling hook to the outside of the cave, Crandell somehow hears that sound, even though he is standing a great distance away.