omg Dee poor Melissa, im so sorry to hear what happened that must have been terrifying for you all.
When you get some time please tell us how she is doing, were they not able to save the part that come off? i would probably feel the way you have descrved but please dont, it was a complete accident and there was probably no way avoiding it.
ohhh poor Melissa i hope she is feeling ok. i hope Bree is ok too totally not her fault either.