As some people mindlessly click through multiple prompts, I would take it a step further, and given the seriousness of such an alert, I would prompt the user for an e-signature. I would require them to re-enter their user name and password, with a certification that they are aware that they are sending such a grave alert. Make them do a little more than click an "OK" prompt.
I might even make them do one of those certification exercises where to prove "they're not a robot," make them pick out tiles that contain faces of people, before they proceed.
You point is probably EXACTLY what happened. They brought up the wrong event and just “okay” buttoned their way through.
One of the things my system does, for example, is that it will make deletions a positive action. This means that if you are just clicking through you will answer the “hold” question incorrectly and the data will not be deleted.