"Failing over" in this context most likely means either migrating to some replica (say doing a dead master mysql promotion) or spinning up some backup storage system to serve master reads/writes.
In this context, "failing over" means switching the active system to a replica. Which means their primary data storage system had some issue, and they were switching to a secondary data storage system, which hopefully contains the same data (replicated in real time, or nearly real time). Clearly that switch didn't quite work as expected, otherwise it would have taken just a couple of minutes before everything went back to normal...
Sounds like an engineer knee deep in diagnosing the issue.
That person needs our support more than anyone else right now.