so the lesson here should be not to have helpers work on anything so critical.
That isn't your fault. You have to work with the tools you have, including company provided help. You simply cannot do everything yourself.
I worked under a lead hand who said everything three times. It's amazing to see a journeyman electrician be told where to put a device three times and still put it in the opposite corner of the room. Now, I tell my helpers everything at least four times, because three obviously isn't enough.
Your bad luck is to have everything go wrong on one job and have the worst possible results.
On the bright side things can only get better.
I wouldn't count on that. Things can always get worse. It just won't be such a surprise next time.
Thanks for the story. I shared it with a co-worker and I think we both feel a little better about our own jobs.