Considering how mature Hermione is, it's easy to forget that she's still a minor in the Deathly Hallows, and therefore Bellatrix torturing her and scarring her arm with a term that's almost as bad a the C word is pretty horrendous. Bellatrix revels in inflicting pain and discomfort on others, so this isn't anything new for her and it's behaviour that you expect from this Black. But seeing it happen to Hermione for the first time is truly shocking; especially when the boys can hear her screams from downstairs and do absolutely nothing to help her.
