Add a new Dynastic Rule to the Ruleset.  Call it “Movement” and give it the following text:

Gladiators may Step as a Main Action.  He moves to a laterally or diagonally adjacent Arena Square that is not Blocked.

A Gladiator may spend 2 AP to Shove an adjacent Gladiator.  He moves the other Gladiator into any square that gladiator could legally Step into that is not adjacent to the Shoving Gladiator.  If that causes the other Gladiator to die then the Gladiator who Shoved them is awarded a Frag.