If you're about to touch the production database in a way that could potentially end catastrophically, and there aren't backups, you really should stop and consider the meaning of life before proceeding. Preferably, you decide that backups are the meaning of life, and even if it's an imperfect backup, you decide to manually export the table(s) you're working on. Or something.
He didn't do that. It's a rookie mistake. It cost the company two to three days of development team time to recover from it.
For a community that seems to pride itself on being the best of the bunch at this stuff, I am super surprised that the response here wasn't, "You touched prod without a backup first?! Are you daft?", but was instead, "Miso is a bad company, you need to lawyer up and get what they owe you."
Or, to put it another way: if there were any justice at all, this story would follow rremoncake around for just as long as it follows Miso around.