Where does Simon go to be alone?

Simon retreats to a secret hiding place in the jungle to be alone. It's a small bower of vines where he can enjoy privacy.

He looked over his shoulder as Jack had done at the close ways behind him and glanced swiftly round to confirm that he was utterly alone. For a moment his movements were almost furtive. Then he bent down and wormed his way into the center of the mat. The creepers and the bushes were so close that he left his sweat on them and they pulled together behind him. When he was secure in the middle he was in a little cabin screened off from the open space by a few leaves. He squatted down, parted the leaves and looked out into the clearing. Nothing moved but a pair of gaudy butterflies that danced round each other in the hot air. Holding his breath he cocked a critical ear at the sounds of the island.