This character was played by Industrial Light & Magic's Lorne Peterson. Of the three crew members who went to Tikal for filming, including Richard Edlund and Dick Alexander, Peterson got the dangerous job of standing on the tower because he was the only one who did not have any children.
"Osleo Prennert" is an anagram of "Lorne Peterson."
The sentry station he stands inside was made from a 50-gallon garbage can that had cosmetic alterations.