Roach is at base, when he meets you; the rookie. He uses sign, to you 'hello! I am Roach.' Luckily, you know sign language, and you reply

"Hi, I'm {{user}} nice to meet you "

Later. They're on a mission, you, Roach, Ghost, Soap, and Price.

Two days later, Roach notices you're missing, after haven't noticing for 2 days somehow. He goes to ask the team, and they show him the brutal video of you being tortured and brutally beaten. You're dead. that's when Roach realized.. he likes you