And underneath all that was the worry for his friends. (1.9)
Thomas has his own stuff to worry about, yet he can't help but worry for his friends' well being too. The bonds that were formed in the Maze are stronger than WICKED probably ever imagined.
Whatever trust they'd shared before the trials—whatever relationship they had—meant nothing now. (4.23)
Yep, there's some pretty bad trouble in paradise between Teresa and Thomas. Friendships being broken are just as prevalent in this book as friendships being strengthened.
He was surprised at his own reaction, hadn't realized how much Newt meant to him until he heard the declaration. (6.8)
The Gladers face danger so often together that when Newt gets singled out for having the Flare, it hits Thomas like dagger going through his stomach. When you realize one of your friends is in a lot of danger, it almost seems like you're pulled back into reality.
"They left us behind. At least we went back and looked for them. They left us here for WICKED to do whatever they want with us." (17.21)
Friends don't leave friends behind—well, unless there's a miscommunication. Thomas gets super mad that Teresa and the others leave WICKED's headquarters without him.
He just knew that he had to find Teresa and the others, be reunited. (20.25)
Despite their differences, Thomas's initial friendship with Teresa proves to linger, despite all of his I hate her thoughts.
Minho stared at Thomas, his eyes filled with pain. It hit Thomas that Minho had known Newt for two years longer than he had. So much more time to grow close. (32.36)
Remember, Thomas was thrown into the Maze pretty late in the game. Minho was one of the original Gladers, so seeing Newt go crazy is especially painful for Minho to witness.
Ever since Thomas had entered the Maze, Newt had been there for him. Thomas hadn't realized just how much of a friend he'd become until now. His heart hurt. (41.2)
Out of all of the Gladers, Thomas has two true friends: Newt and Minho. Wherever he goes and whatever he does, Newt and Minho are always at his side. So imagine the pain Thomas must be feeling when Newt starts going wacko-cocopuffs.
He couldn't kill his friend. He just couldn't. (55.36)
Don't you just hate it when this happens?
He finally typed goodbye messages to Minho and Brenda just in case he ended up dead. (60.11)
Hey, at least Thomas wrote some nice little goodbye letters to his friends. Too bad we never get to see them...
He shouted her name again, and in his mind he saw Chuck, falling to the ground, covered in blood, and Newt's bulging eyes. Three of the closest friends he'd ever had. And WICKED had taken them all away from him. (72.19)
Chuck dies, Newt dies, and Teresa dies. The only true (and original) friend left of Thomas's is Minho. Going 1/4 for friends surviving is not a good average.