I loved this! Poor Severus! I really like this pairing.
I also liked that Severus didn't stab the table with the butterknife. I don't know why but I liked that restraint.
I loved that Severus 'wondered if he'd ever have the strength to leave Regulus or the strength to stay. Watching your lover endanger his life like that would be so hard! Toothless, fingerless- ouch! Auror hexes are vicious! AK almost seems more merciful by comparison. Except that there's Skele-gro and even bones can be grown back.