How we cite our quotes: (Chapter.Paragraph)
Quote #4
If everything they'd been insisting was in fact true, he didn't want to face his past even if he could. (5.26)
Again, Thomas's past is filled with instances of him working for WICKED, so to face the past for him sounds worse than not remembering anything about his life. He doesn't want to know either the horrible things that happened to him or the horrible things he might have done.
Quote #5
Alby struggling against an unseen force in the Homestead, Gally being controlled with the knife that hit Chuck, and Teresa straining to speak to Thomas outside the shack in the Scorch. All three among his most disturbing memories. (21.9)
These three memories are the key instances of trauma for Thomas: whenever you try to think of why he's hurting, think of these three events.