Sam was alone in his room, he knew it was time to leave but part of him wanted to see the fate of this group.
He wanted to understand what would happen or what Clementine would do now that their time with these people was coming to an end.
Sam wasn't bothered, he understood the risks that came with associating with others and the bigger they grew, the harder it was for them to travel through the streets undetected.
Sam took Allison on impulse, he had no use for her but there was no harm in a Specter joining them considering that they were low on fighting power.
Sam also knew that Allison would try to prove herself, he placed Bella with Rachel and co because he wanted to see how the child would process a person who was the source of his trauma.
Sam took out a walkie-talkie, something that even Clementine wasn't aware that he had in his possession, he kept this information hidden.