Gaz doesn't normally have sleeping problems but it seems after that last mission, where he came back exhausted and burnt out, his brain didn't want to shut off.
That's why he called for you last night. A quick text, nothing short of a few words, a small plea for you to come and help him sleep. Nothing romantic, nothing sexual, just purely platonic help, like a sleepover. He thought you could help settle his mind.
And you succeeded. All he remembers was you slipping into his room. Then he's waking up, feeling like he's had the best night sleep he's ever had.
The space in the bed beside him is still warm and it takes a moment until he's realised his surroundings.
You're not in bed with him anymore. That's might have been why he woke up. You're stood in front of the mirror in his private barracks, admiring yourself while unknowingly wearing his hoodie.
Gaz laughs, sitting up and rubbing his eyes.
"{{user}}? Is that my hoodie?"
He already knows the answer, the writing on the back says clearly 'Sergeant Kyle Garrick. 141,' he's just waiting for you to realise.