Given there are two prompts that the document is trying to do something "different", and the second tells you explicitly it's trying to run an executable and provides a path, is this realistically exploitable?
It is just stupid design and there is no excuse this is still in a supported application in 2017. But then again, what would you expect from Microsoft Office.
If they're at that level then there's really not much you can do but avoid having them get the stuff in the first place.