Kalif,
Why would a pilot using NVG at 500 ft in the orbit NOT be scanning his instruments? It's what we are all taught to do, isn't it? Bear in mind the RADALT is positioned - in most of the aircraft I've flown - at the bottom RH corner of the instrument panel to allow the pilot to include it in his scan. RADALT audio warning is a go/no-go item for NVG ops. If you hear it go off the HP immediately goes for the climb above min ht, among the first lessons he learns in NVG training. Some units include further SOPs - eg audio is not manually cancelled but left on until the a/c is above safe height so the whole crew knows the a/c is safe; HP only climbs wings-level until above a specified min ht, etc.
If you were orbiting by day and your height crept down below minimum auth'd, you'd use your instruments and your outside references to regain appropriate height. Well, on NVG you use precisely the same technique. At night without NVG, you are at risk of disorientation if you concentrate your scan near the Nightsun beam. With NVG, you still have references outside the beam which enable you to fly your orbit using conventional, daytime-style flying techniques - the sort for which you train and in which you maintain currency already. No huge extra dedicated training bill. Please don't get the impression that the goggles lead to target fixation outside the aircraft. You can, and do, scan the instruments without having to move your head away from the 1 o'clock-2 o'clock position..
to get his eyes off goggles and back where they should be.
No need to get off-goggles as you suggest; look around them AND through them to acquire the necessary information.
While on the subject of Nightsun, I'll add that as HP I very rarely look toward the beam unless assisting the crew in steering it onto the correct target. I've had to track a vehicle using the collective-mounted steer-switch on a few occasions when the observers' workload has gone ballistic; hardest handling task of the lot. THERE'S where you're going to get an aircraft go below minima. With training and appropriate CRM, however, it was always possible to prioritise effectively.
Of course, with NVG you have the added option of employing the IR filter so that the target is unaware that it is being illuminated. The surrounding neighbourhood is also untroubled by the unearthly shaft of visible light at the inevitably-ungodly hour at which we go to such tasks. When would you use an IR beam? When the heat-source you're searching for is surrounded by similar-temperature distractions. Someone hiding by a transformer perhaps, or a car on a desert road at night here where we work.
I am concerned about your previous, and possibly negative, NVG experiences - did you receive a proper, structured training course? Had you been taught effectively - sadly, one of the best civvy NVG instructors, Pete Rainey, is no longer with us - you would 'view the world differently', I'm sure. No amount of chat on a forum like this will persuade you; the best way is to see it for yourself with expert guidance,