Encyclo
I'd like more info on which 412 you're talking about. If you don't mind PMing me, that would be great.
When you say "the 412" it sounds like you may not know (as I didn't 'til I was involved in one of these incidents) that there have been many -- far more than you would imagine, and far more than Bell (whomever they are today) acknowledge. And my info so far shows that the standard proections you suggest will not necessarily prevent or even alert you to a problem. The most common reason is failiure of an apparently healthy part. I will be happy to share my findings with you when I'm done.
In the meantime, if you're flying a 212 or 412 and want the doors open, the safest way to do that is to fly with the doors removed.
Grizz