Amon crawled slowly and silently to the one whose position was closest to him. He could not see his prey clearly, only his general position. He did not rise to check that he was going in the right direction. Doing that would only expose his position. Those boys said that they had taken Cat-eye pills. He didn't know how effective of a night vision ability those pills granted them, but he was not taking any risk.
He did not hear any more sound from those boys, meaning they were stationary. He took his time to make his way over.
Once he was in the vicinity, he still did not act recklessly. He circled around to a part where his back was facing a wall that had no openings. The three boys were paying attention to the entrances into this cavern hall, which were the various hole openings on the wall, and there were many. They would not waste time observing the part of the wall that had no openings, so that's the location Amon knew to be the safest for making an observation.