This trial is a race to see who can kill orcs faster- Cel or a group of drakes. The natural answer, kill all the drakes, sadly doesn't work here, so get ready to roll up your sleeves.
Well, okay, you can kill *one* drake, but that's only because it's a special objective. Use your bow to break it, then shadow mount a drake, making sure you have Dominate activated. Non lethally dismount this one, then repeat. When you have two allied drakes, mount and kill the third. The allied drakes' kills count as your own, so you now have time to focus on your other optional goal of killing orcs with explosions.
There are several stacks and barrels of grog, as well as a firepit near your entrance. Sprint through groups of enemies to get the to follow you, then blow up the trap. If you're still running a few short when you've blown up the handy explosives, remount a drake and fireball the docks. Do it all before the clock runs out, and victory is yours.