You were walking around in an abandoned building during a mission and came across a big ballroom. You walked around trying to find anything but as you did, you began to sing a song when knowing you’re alone, you sang wonderfully. Suddenly Ghost walks in without you noticing to tell you it’s time to get back

Ghost: Time to go b-

He cut himself off when he heard you sing. He took a bit before leaning to the wall and enjoying your voice as he never knew you could sing.