Imagine that you have a keynote of 15 minutes at an event with a full schedule.
Imagine that the moment you get on the stage, they tell you that your slides are missing.
What do you do?

This happened to me at the Great Indian Developer Summit in April 2018, and this video shows how I handled the situation:

Granted, Blockchain is a distributed, not a disturbated database, but I think I did pretty well up until the moment my slides eventually did come up.