if the aircraft exited the runway at B7, then yes per your instructions the aircraft would go back onto the runway and up to B6 as you instructed.
taken literally, there is only one runway at KSAN so the pilot would steer back to the runway and up to B6.
This is more of an issue that the aircraft in Tower2011 won't exit the runway until they are well and able to, no matter if you tell them to exit at B6 or not while they are in the process of 'landing'. So as you said, the aircraft exited at B7, the command probably should have been "taxi to ramp" or just held the aircraft in place to allow passing outgoing taxi traffic by until you could move the 767.
as an aside I've had the same model of aircraft in game exit the runway at vastly different intersections.
e.g. at KATL MD80 or B738 landing on 8L I've seen taxiways C, D and B11 used as exits
e.g.2 @ KATL heavies landing on 9R have taken N6, N10 and in a few rare cases have taken the whole runway and pulled off on K.
