Old Fashioned Murder

What was the point of killing Milton Schaeffer?

Setting up a fake robbery to pull an insurance scam is understandable and it would save the museum and they wouldn’t lose the artefacts.

Killing Edward made some sense because he wanted to shut down the museum and sell everything and it was Ruth’s whole life.

But why kill the guard? What was the point of that?

Edit: ok so I just realized why. It was to set up Edward’s murder to make it look like the guard had killed him. But what a crazy scheme!