Robin,
Killing all the power would do absolutely nothing to avert or avoid that wreck. (It took place in California)
The Engineer of the train that got hit would probably have placed his train in emergency, which would have opened the PCS switch on the lead unit (PCS = Pneumatic COntrol Switch). This would have disabled the engineer from doing anything further with the throttle or dynamic braking. There is a locomotive kill feature on the throttle stand and it is used in case a locomotive catches fire or if for some reason there is danger to the crew caused by the large amount of diesel fuel carried. There is no reason for an engineer to leave his seat to kill an entire consist should the situation so deserve.
Had the Engineer on the consist not placed his consist into Emergency, he could have applied full service, gone into dynamic braking or even thrown the reverser from forward into reverse to attempt to avoid the accident. The reason that the tape turns blue at the end is from the extreme impact between the locomotives which caused the hard drive on the camera to become inoperable. These use a Hard drive which overwrites itself every couple of hours.
The problem is, whether the locomotive that got hit was in emergency or not, the accident could not have been avoided under the scenario shown as the locomotive which was supposed to stay in the clear of the turnout was not slowing down fast enough to avoid an accident. That's the way it is on a single track Railroad. There's only one track and if another train is occupying it, your train can't.
The thing that probably saved the engineer of the train lined into the siding (and taking the video) was that the wreck was a glancing blow that took place on the Fireman's side of the cab instead of a true head-on.
That video is the nightmare of every Railroader that I know.
Rick Steele
