Stealth: Despite one noisy dwarf, none of the gargoyles move as the group closes in on the amphitheater.
Camp: The first thing the group encounters are three tents surround a smoldering campfire southeast of the amphitheater. A search of the camp reveals one empty bedroll in each tent. Tracks, eight pairs of medium size bipedal footprints and one wavy line, lead way from the camp to a tunnel at one of the ends of the amphitheater.
Sinkhole: In the center of the amphitheater is a massive sinkhole. Perhaps this is how the dragon enters?