The Times has an article on what happened. "Instead of seeing and avoiding Flight 5342, Captain Lobach continued flying straight at it. Investigators might never know why. There is no indication that she was suffering from health issues at the time or that a medical event affected her during those final moments aboard the Black Hawk, according to friends and people familiar with the crash investigation, which included autopsies and performance log reviews.
Two seconds after the controller’s cut out instruction about passing behind the jet, Warrant Officer Eaves replied, affirming for the second time that the Black Hawk saw the traffic. “PAT two-five has the aircraft in sight. Request visual separation,” he said. “Vis[ual] sep[aration] approved,” the controller replied.
It was their last communication. The Black Hawk was 15 seconds away from crossing paths with the jet. Warrant Officer Eaves then turned his attention to Captain Lobach. He told her he believed that air traffic control wanted them to turn left, toward the east river bank. Turning left would have opened up more space between the helicopter and Flight 5342, which was heading for Runway 33 at an altitude of roughly 300 feet.
She did not turn left."