Too tired to protest or open his eyes, Terrance sunk into sleep yet even then his face didn't relax completely. He'd learned that sleep was never a good thing since they always brought about dreams so didn't like to sleep unless he absolutely had to. He always looked forward to those rare moments when he had no dreams at all. Sleeping also meant being vulnerable and slow to act if a monster decided to attack. While traveling he'd had to sleep and Thanos had stood guard then, it didn't mean that Terrance had trusted him completely, more like he had no other choice and it was the lesser of the two evils. Not to say that he didn't trust the other teen, but it was rather complicated. It had been ever since a strange little boy had clung onto him and promised to protect him after declaring declaring, "I like you." Terrance had just thought Thanos was a little weirdo who had no concept of personal boundaries.
His concept of personal boundaries was still non existant, but Terrance had gotten used to it. While traveling they'd had to huddle together to keep warm before Thanos had figured out how to get a frie going even when it was raining. He'd come to rely on Thanos and part of Terrance did not like that. That was why he'd only grudgingly allow himself to sleep deeply every now and then. Because of pushing himself this was one of those times.
SILENCE is better than UNMEANING words