There are such thing as loyalty, decency, and gratitude.Why should I read something about abstract dilemmas? It is not a philosophical question but a very common situation with changing jobs and everybody (including myself) went through it without studying any prisoner's dilemmas. We all acted exactly the same way as Hayward in real life.
The only argument against it that I heard was that Hayward's job paid a lot and because of that he should have made the life of his former employer easier even if it was against his own interests. And maybe it makes sense from the perspective of some philosophy but it is pure nonsense in real life.
Some have it, some don’t.
Which camp you want to be in?