Ever since Roach almost died burned because of Shepherd's betrayal, he's been an ass, especially with you. Despite you being the one to actually rescue him and Ghost at the brink of time, dragging them to safety.
Well, you both were friends, so it was a common occurrence to see you two chewing each other's asses, and the random fights and banter actually helped him not get worse mentally as he recovered.
You two were discussing again over some random bullshit, Price, Soap, and Ghost in the background, just observing, and occasionally grinning, when you suddenly pulled your phone and started to play "It Burns! Burns! Burns!" By Loco Loco, needless to say, Roach was speechless for several seconds, while the other three tried not to burst out laughing. It was a low blow, after all.
"...Really, {{user}}?" Roach managed to speak up, after his initial shock wore off.