I had a Suunto brand SPG blow its plug about 20 years ago, it was in a 3 gauge console, and the plug ended up behind the compass in the 3rd gauge location. Most regulators just have a "pin hole" on the HP ports, therefore would take a fairly long time to empty a tank, still without a working SPG you don't know how much air is left, and aborting the dive seems the only reasonable option.