An ally's fall makes clear that withdrawal is the better part of valor.

Encounter   ✦     Martial
Immediate Reaction      Personal

Trigger: An ally within 5 squares of you falls unconscious.

Effect: You can shift 1 square and then move up to your speed + 2. You must end the move farther from your ally than you were when you began the move.

Published in The Book of Vile Darkness, page(s) 1-14.