Sadly I cannot, since the source is an ex-Googler I know in person who was there personally. While I fully believe the story, I’m just some rando on the Internet, so you’re welcome to take it with the appropriate pile of salt.

At which point you have to slurp down a few hundred terabytes from the other datacenters when the power turns back on.

This is why Google datacenter managers hesitate to turn off the power even when an employee is in the process of getting electrocuted.