In the elevator tomas grabs cia's hand to show her that he is there for her and will be there to protect her. Pg.73: "A hand takes mine and holds fast. I turn and looks into Tomas's eyes.
Planning the meetup
Tomas and Cia are planning to meet up at the tallest building in Chicago. This shows that while he could do it by himself and complete the test by himself he is going to try his best to stick by Cia and keep her safe. Pg. 136: "Tomas is one step ahead of me. Talking quietly in my ear, he tells me to find the tallest building still standing. Go there. He'll meet me."
Cia tried to jump off the bridge and fell she is hanging on the side but she's about to fall. Tomas found her and helped bring her to safety. This shows that he wants to keep her safe and wouldn't leave her by herself. Pg. 157: For the realization that I am being pulled up and not pushed away to bloom into understanding. My heart is pounding. I can hardly breathe but I manage to croak out, "Thanks," as Tomas's face swims in front of me."