If I was fleeing in fear for my life, whether or not i held on to my shield would be entirely dependent on context. It might be that dropping everything possible and running would save me. If I’m under fire, I don’t think I’d let go of that shield for anything – I can’t sidestep a cross bow bolt when jogging, but a big shield would cover my torso.
There should be multiple possible outcomes as to what a character does when he (she in the future?) routes. Example:
(a) No weapon drop
(b) Drops one item
(c) Drops all items