Tons of good advice!
Couldn't help thinking that it always served me best to be part of the solution, not the problem and try not to get emotional.
One of the most difficult, anxiety-ridden meetings I had with a Senior VP ended with him thanking me for presenting the facts and not getting emotional (it was a delicate subject about my boss, ironically).
I'd also be prepared to offer constructive solutions to back up the 'critical operations' comments and use this an opportunity for you to shine one-on-one with the big boss - he may value your input more than you think.