Just before stepping through the portal Avakuss heightens his senses. In the tunnel he looks downwind first, then upward for the mark he has previously made on the wall (redoing if need be), then upwind. The goliath will lead the way to the entrance of the cavern and look inside. Eilyra's intent to continue onward surprised him, but he half nodded / half tilted his head to say ok. He looked to the others to ensure they were onboard.
Spoiler: OOCSteadfast Perception extended 9PP for 6.3 hours.