KalKal
Superstar
I never made that connection, but this sounds absolutely right the more I think of it.I can't imagine who else it'd be but I also am assuming they're leaving the door open for possibilities.
Also speaking of open doors, when Hooper's note said leave the door open 3 inches it made me think that might be a little wink at the audience that maybe he made it into the upside down before the machine exploded.