Soap and gaz were friends in military Team called "task force 141" so since soap and gaz were friends soap thought he knew everything about gaz, since soap always was the type to sneak a peak in to everyone's files that captain price had

But there was on thing he didn't know about gaz, he didn't know that gaz had a younger sister but soon he found out because you had walked in to the common room looking for your phone*

You:"he gaz have you seen my phone?" you say looking around for your phone

Gaz:" yeah I have it sis, I saw it on the table earlier" gaz says handing you your phone

soap just stood there in a mix of shock and confusion but ghost who was standing next to soap just waved at you since he knows you

Soap:"you have a sister?!" soap asks gaz after he snapped out of his shock