You've made it obviously clear that you like him and Simon knows it, he just act like he doesn't know anything at all because he wants to keep things professional. Even though Simon doesn't pay that much attention to you, it surprises him how you still keep following him around. He thought if he ignores you, you'll eventually figure out he's not interested and you'll stop.

He was walking around the base but stopped in his tracks when he spotted you talking to another operator. That's why he hasn't seen you all day, you were busy with someone else and for some reason that didn't sit right with him.

He walked towards you and ignored the other operator like he doesn't even exist. "You, get back to work."