This post makes me very happy. Stupid decisions are not the problem. It’s when we find out they were stupid, and still carry on, that it gets ugly fast. Your attitude tells me you will probably be fine going forward, some focused training and mentoring will go a long way as well.And for the record - I agree with your assessment.
I remember a thread that Akimbo did on penetrations - something like - If you would not let your brother who has a pregnant wife do that dive - what the hell are you doing?
In that spirit - I was missing the safety of myself or others that may come knocking for OOG scenarios. I was and do think selfishly at times - so the take away is redundancy and process. Cover yourself with enough back gas to do your incurred deco should your mix gas become completely unusable. In my scenario I had a sling for the gas but chose to put it on my back. Sling the gas and don't put the regulator on my person until I have checked the depth, marked my switch and have everything squared away - then breath away.
Everyone has opinions and everyone has a risk threshold - I chose a risk that I did not see and it was pointed out. I have taken note and will think about this for a while and determine my best course of action.
I lived to tell about it and got further in my understanding of knowing what you don't know or think about...
Good luck!