This is a very interesting thread.
Very sad for all involved.
I have not read the details for a long time, but a few points that come to mind.
1. Press switch/knob not the clearest/ind/de-tents.
2. Press mode light/ind cluster as above, waiting to happen.
3. Boeing made previous hi-lights of the above. "Beware"
4. MM checks of this system did not state switch positions after checks.
From memory, some layover/nightstop aircraft would have the outflow valve closed for various reasons, I think method was often by putting selector to Man, run closed, pull aircraft power and then select mode to Auto, next power up all back to normal, no problems.
Thinking about item 2 above, did we not see a good example of this indicator type on a LH 747 at NBO (1975ish ???) that was poss external lighting issues, but even a filament or two failures may not be of help, again thinking back, I recall Green was Auto and Blue was Man ????
Lets hope some lessons are learnt and save others in the future.
I also find it hard to understand how the Engineer is finding himself in this position, what do they say about the law ??????
My last thought for the day, on turnaround/transit aircraft, check panels well, nightstop/layover aircraft check panels well, after maint performed check panels well, after cockpit cleaning check panels well. Don't use Autoscan, use Manscan and keep it interesting(rev scan using other hand works for me)
Cheers all.....