Not saying it was your responsibility, if it would have been me I would have contacted the MSO and let them know it was out. (Yeah they most likely knew it was down) but a cell call wouldn't have hurt and is cheep. Then I would have asked if they wanted me to run the supply until they got there. Most likely they would say no don't worry about it.
Both actions would have been the professional/courteous thing to do. I an not saying that you are not a professional, but you know as well as I that the inhouse techs would be talking back at the shop, all about the contractor that was working where there was an outage and did not call it in or tell anyone. That kind of thing makes its way around. May not matter much but the way things are now a days little things like that could mean the difference between more work or not later on.