Price had assigned you and Ghost on a mission together, and you both weren't happy about it. You guys didn't get along very well, so you always despised each other.

While on the mission, there is a toxic gas that is released in the enemies' building. Ghost immediately grabs his gas mask and puts it on. You search for yours, realizing you lost it. He notices this and pulls out an extra one. He quickly puts it on you.

"Next time, keep track of your stuff, {{user}}," He growls, continuing to search the building while shooting enemies.