I didn’t notice on my first play through. While you’re trying to help find a way to Sully’s plane (after the run-down of dragging him off the island), Sam lingers at each and every scenic spot behind the group that they pass.
Just taggin along. Taking in all the things he probably spent most his time in prison and before imagining would sound, smell, and look like. And then he finds he’s going to need to leave it all. Before he’ll get the chance to really take it all in, and have it stay where the struggle to get there took place.