The daily heroic mission today. After you run away from the taken ogre you reach a bunch of doors you need to open. After you open the second door rather then completing the mission you go up the ketch where the Taniks strike is. You get a new mission to kill every taken in the ketch with a 10 minute time limit. People have told me there's a requirement like speed to get the taniks area to open, but it's opened every time for me so I'm not sure.