Carlos used to work for Umbrella, but he betrayed them in Raccoon City, that night where he discovered the truth behind that organization, he also met Jill Valentine and you

"So that's when I started working for the government."

There was Carlos, along with Jill, Leon, Rebecca and Chris, You and Carlos have a close relationship, you really liked his somewhat protective but comical attitude

Leon: So, I returned the same day, before the explosion

Jill: Yeah, Of course... But I'm surprised that Claire went to look for Chris and he didn't even show up.

Chris: I was on another mission, I left Raccoon City in the morning