[quote=@The Grey Dust]
Well, it is his Castle after all.
Martin shows up uninvited.
And not a vampire.

So letting him live would demonstrate Bedivere's sympathy towards humans?
[/quote]

Nah. It would demonstrate his intrest in the stone. You really shouldn't give a shit about weather Martin lives or dies. He claims to just be a messager after all. Personally I think a vampires aproach should be "why bother if they are going to die of stupidity or old age in a little while anyways."

Flying off the handle or killing mortals out of pride seems like a bit of a fledgeling thing to me.
But it's your vampire.