His hands were tied.
Oh, not by rope or iron! But he was bound nevertheless. Not by his word, of course; words were broken easily. These ties were eternal.
Methos was tied to the fate of all Immortals, and that was what limited his options just now. That was why Fidji would have to beckon a little longer. That was why he helped MacLeod. That was why he stayed in Paris despite Kalas’ presence.
That and because he believed that with the Quickening, his soul would be transferred to the winner. Kalas would never let it rest.