Last week we had an employee collapse in a different office. A couple other employees attempted CPR, but since nobody knew it, they had to be talked through it by the 911 dispatcher over the phone. He didn't survive. I don't know enough details to know that a trained rescuer could have made a difference, but it's certainly possible.

I think the survival lesson is that you can be as prepared and equipped as possible, but if the people around you (friends, family, coworkers, neighbors) aren't at all, you've got a big honking gap in your plan.