So I have a level 13 thief that gets scaled down to level 10 when facing Bercilak. I try kiting Berc, but when I get out of range, he runs back, regenerating his health. Then I start over. I try to face him head to head after a little kiting, but then I die in about 4 hits. Ive tried to stealth, but he just runs back, once again regaining his health. I have some good gear. Dual wielding blue pistols, and using two knives. Any advice?