[he does understand what she means by "lost", and what she's trying to tell him.

but how can he let it go when he can still... clearly see the logic behind the actions, as crazy as they still seem?]

... not being able to protect you--I can handle that.

["handle". by killing whoever did her harm and possibly even gutting them and pulling out pieces of flesh--he feels sick thinking about the vicious and hollow satisfaction.]

But this... was different. If that guy hadn't been there at the fountain...

[he definitely would have gone after her and who knows.]