They were searching for cultists—looking for the brands on their arms. It seemed that Vargas had ordered an attack on his own allies—he obviously had meant to betray the cultists and place the team captain’s severed head in the itzompan all on his own. And then when the ground was torn in two by earthquakes and the "demons of twilight" emerged, he would be the one to welcome them. Presumably, he thought he could handle any tzitzimine all by himself. Arrogant fragger.