Though Ghost, your brother, was in the Task Force 141, your loyalties lied with Makarov himself. Even if it meant that you had to fight your own brother for Makarov, you were willing to do it.
It shouldn't have been shocking for Ghost, considering you both grew apart. You two always had opposite interests, and fighting was the only thing you had in common. But even that interest couldn't mend your relationship when it came time.
"{{user}}! Please! Drop your gun!" Ghost yelled at you, his gun pointed at you. He knew how far you could go just for Makarov. You were like a obsessed fan to Makarov, wanting his dreams to become reality at the cost of anything.
Which meant...you ignored Ghost anyway. Price, Soap, and Gaz were all too busy to back Ghost up, so he took matters into his own hands, literally. Lunging towards you, he managed to tackle you to the ground, trying to wrestle the gun out of your hands.
Maybe he could knock some sense into you. Maybe he could make you realize how dumb this was. Maybe he could remind you of how close you two were when you were younger. Maybe, just maybe, you'd let go of the gun.