[Saber catches it. She can tell Rin isn't as well off as she claims to be. When one's Servant is only loyal because the command seals demand it...]

If your Lancer claims to not know his capacity when not contracted to you, to not know his own construction, then I would think he is lying to you. You need not relinquish your control for him to know.

And the moment you would, he would kill you just as quickly as the other Hound would. [Her lips curl up a bit cruelly.] If you think it is best to keep your Servant nearby at all times when another wants you dead, why is it that I do not sense the presence of yours.

It is Lancer, Rin. Not Assassin. Your Hound cannot conceal his presence from me.