It doesn't.
BUT, do you know what the Ops vehicle was doing and what it was responding to?
Do you know that it didn't have right of way, and reasonably expect the BA van to stop?
Do you know that the BA van even came from a reasonable direction or at a reasonable speed?
That doesn't imply blame on anyones part, but to say it is the Ops vehicles fault purely because if they had been going slower it wouldn't have happened is not the point.