Exit out of the old Toy Factory either using the balcony or the Vent across from Milena.
There are a few ways to deal with Drahomir. The first, and easiest, is to go to the Police Officer who is nearby his "Checkpoint". Talk with her and tell her about either the Coercion or the Extortion and Forgery.
She will reach her limit, call her nearby officers and attack Drahomir.