A Bronx woman who has accused an NYPD cop of breaking into her apartment during a drunken early morning attack told investigators that he viciously beat her in her bed, punching her more than 20 times. Officer Eugene Donnelly, clad only in his underwear, eventually fled — but not before taking a drink of milk from her refrigerator, a source familiar with the woman’s account told the Daily News. The woman told investigators she was awakened at 5:30 a.m. by a boom — the sound as Donnelly busted her front door open, according to the source familiar with her account....