I don't know and why even stay there that long? I guess he didn't hear the drone due to white noise, but that was really bad play from him. Possibly cost them the map. Moment he heard the drone he should have dashed and smoked away.
Good Sovas act like they haven't seen you lurking but they actually did. They give their mates the info and you get easily killed because you think the guy who walks towards you won't know youre there.
He just avoided to let them see more than they are allowed to see. Theres no right or wrong with destroying the Drone. He needed someone to assist him in this aggressive sneaky pushes so he can even make it worth but G2 not really ready for the really big Teamwork plays.