MFW I accidentally ran "rm -rf /" on my work PC last week. This is what happens when I skip my morning coffee.

it prob too late cause u gotta do it before the journals get overwritten, but next time try using ext4magic (assuming it was ext. if not there other data recovery) to recover the data. I did somthing similar to you ( thought I was in a home subfolder, turns out I was in /.) On a related note if u want to delete something so it can NOT be recovered, use shred command.

No sudo, no harm! Am I right?

Next time, try rm -rf / --no-preserve-root
Then it will actually work.