In the book "The Death Cure" Thomas gets reunited with his friends after undergoing complete isolation for three weeks. But then the Rat Man informs him that "All of you went through different types of tests for Phase three of the Trials, We'd hoped to have the killzone patterns mapped out by the end of the second phase, but we had to improvise in order to push further." (Dashner 15-16). Thomas then begins to think what tests his friends must have been put through because he knew for a fact that WICKED could do much worse then just isolation in the room.
"Sitting scattered among a dozen or so rows of seats were his friends , safe and healthy-looking. The Gladers and girls of Group B. Minho. Frypan. Newt. Aris. Sonya. Harriet." (Dashner 16). So as Thomas sees his friends, all healthy and alive he's over whelmed with joy, up until the Rat Man makes another announcement.
He informs all of them that for Phase Four of the Trials, WICKED is allowing the "subjects" to chose if they want to get their memories back from before they were put into the Maze. Thomas and his friends Minho and Newt, find it strange that now suddenly WICKED is willing to give them their memories back after keeping them from all of the Gladers for all this time. So as everyone makes their decision if they want to remember their past or not Thomas, Minho and Newt start to discuss. They agree on choosing not to get their memories back because they still don't trust WICKED and don't want to give them another chance to mess with their brains. This shows the personality of the characters becuase their choices and way of thinking reflect on who they are. Thomas is more of a independent and careful thinking where as Minho is someone who makes rash decisions and can be hot-tempered. Then theres Newt, who's the "glue" of the group because he's level headed and reasonable and can also seem to get the group back on track when they start to fall apart. So even though all of them have different personalities, their way of thinking is still very similar. "'I've heard enough bloody arguments. I'm not getting on one of those beds.'
Minho reached over and squeezed Newt's shoulder. 'Me neither.'
'Same here,' Thomas said." (Dashner 31). So they all decide not to get their memories back even though everyone else is. Their next step, is to break out of WICKED for good.