On FB, I believe 2 (Circus Freaks & Carnival Queen) cannot be killed before it goes into critical mode on the last day. When it goes into critical the rewards are reduced, unless you're on to hit it every 20 minutes and you can probably make that back (I don't know this for sure as I work during the week and cannot attack the WB's frequently.) So they cannot be killed within the time allotted with Kano's regular 4-hour pace, they have to be attacked every 20 minutes to bring them down.
Last edited: Dec 20, 2013