You have to get his hp down to 90% for him to flee. Was fighting him with another 5-6 players for about 10-15 mins and we got him down to 95%. His bounry only rewards 1 mark. Its a waste of my time and effort when I can kill a bounty in 5 minutes to get 8 marks. Honestly devs would you see yourselves wasting your time in doing this when much better options for earning marks are available? It really ruins the feel of this celebration when an iconic character is handled his way. Make the rewards equal the effort.