The Word Made Flesh

Why would two Eastern European meatboys want to whack an innocent cab driver? That's the question that occurs to Gilrein as Raban and Blumfeld press the gun barrel into his mouth. Does it have something to do with the ritual death-by-flensing of Leo Tani? Or does it involve Gilrein's ex-lover, now working as a librarian for a bibliomaniac gangster?