Determine which
location it could
step to using its normal
movement that would be
closest to the caster that triggered it. For instance, assume the
Sturmgeist is at location S, and the
spellcaster is at location C: Because the Sturmgeist has the
airborne ability, it is able to get from S to C in one step, so it must do so, leaving it
zero steps away from the caster. It cannot
move to A or B, because those locations are still one step away from the caster, which is further than zero steps.