Amazingly lucky. Once again reminding that S92A gearbox is a deathtrap...it cannot actually run dry. Recall their Part 29 certification run-dry "extremely remote" clause basis was on the oil leak occurring in the cooler circuit, and the mitigation was to bypass the cooler loop.
If you lose oil from the MGB itself for any other reason (i.e. filter mount like Cougar, or literally any other main case penetration) then you're hosed.
8 minutes.