Probably just have a last gathering with the ones I care about. If that wasn't possible, just create a recording to send out to them to show appreciation and say goodbyes. There's no other way to really get to all of those that are close to me otherwise.
I'd like to think I'd handle something like that as calm as one can, but there's really no way of knowing unless it actually happens; but obviously 10 minutes isn't realistic. It's all perspective.