The scene didn’t work for me. It still seems pretty plausible based on the reality of what happened during the war. The Michelin Rubber Plantation, the largest in Vietnam, continued to operate throughout the war. It was a staging area for North Vietnamese and Viet Cong forces. A number of battles were fought over the area with the US paying for damage to rubber trees. The Viet Cong basically let the plantation operate as it did while the French were still in charge. The assumption was that they were being paid off by Michelin. It takes money to run an insurgency.
I’ve also seen mentions of rubber plantations in memoirs that IIRC weren’t Michelin. ISTR they were smaller and also untouched by the VC. Again the assumption of being paid off to ignore the plantation is a part of the story.
That sense of implausibility is part of the reality of the Vietnam War. Sometimes life is so strange it doesn’t work well in fiction.