It's time we showed the locals what us civilized folk do with beasts like them.
Notes
Follow the scout out, then hop on his mount after he does. Prepare for a long ride on horseback back to Amberpine, chased by worgen. Use the abilities provided: #1 is a quick-casting, 5 second cooldown (appears to have been none at some point) AoE firebomb which will kill the worgen in two ticks, #2 is a PBAoE trample on a reasonably short cooldown (3 seconds), momentarily stunning attackers, #3 causes the horse to gallop for a few seconds, on a medium-length (15 seconds or so) cooldown.
Cut Scene
You let the scout out of the cage
Freed Alliance Scout says: Were you bitten?
Freed Alliance Scout says: Answer me! Were you bloody bitten?
Freed Alliance Scout says: You don't even know, do you? The trappers? They're not human... we have to get out of here! Come, quick!
The scout leads you to some horses behind the building, one with alliance livery.
Freed Alliance Scout says: Take Ducal's horse, he's one of them now!
Freed Alliance Scout says: There's lamp oil in the back - make use of it. The fiends hate fire!
You hop on the horse behind the Scout. The scout then rides the horse to Amberpine Lodge, with you dropping firebombs and such on the worgen who are trying to stop you.