I fly the left seat of the 777 and I don't want to go to deep into the ETOPS question (DX, DC or 1X scenarios are outside the scope of what I am looking for).
Just to clarify your statement, it is your interpretaton as well; that after the Critical Fuel Scenario you will still have 15 minutes fuel remaining (also classified as holding fuel). So on the runway you still have 15 minutes, iso of a flame out during the roll?
Greetings O.