I would like to see more of the evidence. The question as to whether or not the failure was initiated from V1 or at 400ft is important. If the latter is true then target speed would have been easily achieved and then some. There's little doubt that a Vmca event occurred. The question is why during a 40 second level segment did speed decay below Vmca. Flying directly into a setting sun would have been a significant factor, the rest is pure speculation.
1. What was the flap position
2. What was the blade angle of the propeller of the simulated failed engine.