Thank you. You are most kind. [Typically that's a polite empty phrase, but he delivers it with enough gentleness of tone it probably sounds like he means it perfectly literally.
He too hopes nothing like that will ever happen again. He's stubbornly decided he won't allow it to ever happen again (he's spent the last few nights reading everything he can find on spinal injuries).]
Your Highness. [She's going to protest at this, he's certain. Where until now he's kept his head bowed in deference, he meets her eyes. Softly, but with perfect sincerity:] I am indebted to you. Anything you wish of me, I will see done.