Easiest way in the medical pavilion. Is to hit them and run to the dental area Vita Chamber, There you can squeeze between the Vita Chamber and they cant touch you (its not a glitch) and unload. I killed 4 first time playing this way.
After that wait for them to go down stairs, and be above them,Hit them ith Grenade launcher, shotgun..wait till they get on you level,and jump down, and repeat.
I also Liked using Target Bullseye. The BD's get damaged and you can move in to Reasearch Photos in action,Hack, and just simply run bye