The bellagio is an amazing visit for most electricians- there is a huge amount of lights and details there. I need to go back and snap about 200 pictures of the ceiling, can lights, and uplit coves for future reference for clients that have the $$$.
Anyways, details of the outage can be seen here: https://www.electrical-contractor.net/ubb/Forum1/HTML/004129.html
scroll to the last post, it has the most info. It's amazing that they will paint the panels to this degree, yet they seemed to have cut corners on their MV distribution system. I guess the reasons for this are private knowledge, but if you have billions to spend, at least put your distribution together right!