Second week at a very large MSP

Am invited to a transition meeting to "listen in" for a project I would be involved in. The task being discussed during this meeting was the migration of ~3000 computers from one domain to another. Computers are spread across 5 different countries. I would be tasked with doing this. I had never done anything like this, and thought it would be a nice opportunity to learn from the pros (after a lot of research and planning). I planned to stay quiet and take notes.

At the beginning of the meeting the transitional architect claims network issues, signs off, and runs away. I did not see him for the rest of the day. His final message to me was "improvise". I am the only representative for the company left in the meeting.

The IT director for this company started the meeting with words to the effect of "We contracted your company for this project because you are the experts..."

The project was a success and the customer was happy, but I was sweating bullets.