Clever men can easily find ways around a geas.

[Kiritsugu was a master at it, self-geasing himself so he couldn't harm another Master and that Master's wife, only to have Maiya kill them after the deal was done.]

Just in case you ever intend on using such magic against me, I possess a Magic Resistance of a high enough rank that a spoken geas is not strong enough to affect me. Most magic cannot affect me.

[It's good to be of the Saber Class.]