The CP-140 Aurora was taking off from Greenwood Canadian Forces Base, Nova Scotia, on a transit mission to Iqaluit, Nunavut, in support of Operation Qimmiq. Thunderstorms had recently passed over the airport and the ground surfaces were wet. During the takeoff roll, the crew observed a flock of birds heading towards the runway. Seeing a conflict and concerned about the risk of collision, the aircraft commander directed the pilot flying to abort the takeoff. During the abort procedure, when the pilot flying selected full reverse on all four propellers, both propellers on the left side of the aircraft went into full reverse; however both propellers on the right side of the aircraft continued to produce some forward thrust. The crew was not successful at keeping the aircraft on the runway and it departed off the left side of the runway approximately 1000 feet before the end. The propellers contacted a Runway Distance Marker and a Precision Approach Path Indicator (PAPI) light. The aircraft plowed through the soft earth and the nose gear collapsed, causing the inside propeller on the right side of the aircraft to strike the ground and break away from the engine. All personnel on board exited the aircraft safely and only minor injuries were incurred. CAUSE FACTORS: ACTIVE CAUSE FACTORS 1. The LRPC delayed calling “Rotate,” and called “Malfunction” after VRO. 2. At approximately 133 KIAS, the LRPFO rapidly retarded the throttles from a high power setting straight into the ground (BETA) range without checking the status of the BETA lights during the movement of the power levers further aft towards ground range/reverse. 3. No. 3 and 4 engines and propellers were not secured using the EHandles when the asymmetric thrust situation occurred. LATENT CAUSE FACTORS 4. The PF is not required to monitor or check critical airspeeds above 80 KIAS. 5. The CP140 Takeoff Abort Procedure does not include direction as to what to do when the power levers are moved into the BETA range, and the associated BETA light does not illuminate. 6. The CP140 Takeoff Abort Procedure does not provide direction as to what to do if the AC decides that the fault does not dictate an abort. 7. The CP140 Takeoff Procedure dictates the initiation of the Takeoff Abort Procedure for any malfunction prior to refusal speed, regardless of the severity, and with no consideration to the speed regime. 8. The standing water on the runway caused reverted rubber hydroplaning and was a contributing factor to the aircraft leaving the hard surface. 9. The LRPC was likely mentally fatigued at the time of the accident, which may have adversely affected his decision making during the takeoff.