Get lots of fake blood, put it in little packets that can be broken easily. Strap someone up with rollerblades and knee pads helmet etc. Put the fake blood pouches on your body, tape them ore something, then go to a area where there's stairs and lots of people and attempt to jump them or roll down them. You fall on purpose and make sure you pop all the fake blood packs (have some in your mouth and helmet). act like your in serious pain and get up all dazed and confused. Quickly stumble or blade away and hide.