The Ninja Epidemic

You dodge to the left, the loud whoosh of the katana sounding loud and dangerously close to your ear. You have escaped death from this ninja and spin around quickly to try and deliver your own death blows with the sais. He dodges your attack easily.

You stand there facing one another for a short time when you start to wonder where the other ninja went. What ever happened to the third one?

Do you glance around for the third ninja, or stay focused on the ninja before you?