He knew this was likely his last mission, unsure if he would ever come back and see your face ever again. He didn’t want tell you about his worry, so he let you do his eyeblack. Ghost wanted to give you one last memory before his potential impending death.

Ghost blankly stared off into the distance as you blended the makeup on his face, too far deep in despair to look into your eyes. If he were to see your giddy smile his heart would probably break even more than it already was.