[souffle]

I am so sorry to hear this. The back flipping she suffered make it almost certain she was suffering from an inherited neurological disorder which is well known in robos. It is most likely that she passed very quickly and painlessly from a stroke or brain haemorrhage and she would have been gone in an instant and felt nothing.
The behavior in disposing of the body is a natural instinct in most small animals so don't fret about it. In the wild a dead animal would attract predators so by instinct they try and get rid of it usually by eating it. I hope Luna is OK. I would advise you keep her alone now and do a cage clean and let her settle. She will be OK once she gets used to it and hopefully will be friendly with you and enjoy coming out.
Run free at the bridge Penny free from your illness now x