A psychologist was slashed to death in her office building at 79th Street and York last night. Another therapist was seriously injured; the suspect is still at large. Police believe that Dr. Kathryn Faughey was killed by a patient during a 9PM session. Dr. Kent Shinback, a colleague in the same practice, ran into Faughey's office when he heard her screaming and tried to stop the patient, but he was, per the Daily News, "slashed......