Yeah I did consider just killing it, I'm going to keep an eye on it for a few days with a gun to it just in case.
I was lucky in that my DB backups were working so all my persistence wax backed up to S3. I think I could stand up another one in an hour.
Unfortunately I didn't keep an image no. I almost didn't have the foresight to investigate before yeeting the whole box into the sun!
Enable connection tracking (if it's not already) and keep looking at the conntrack entires. That's a good way to spot random things doing naughty stuff.