How many of your 9 lives did you use up with this one? You two are very lucky.

Is it a quill type headset (or ahead)?

Might be an interesting study in failure analysis. I suspect it is fatigue failure. If you could examine the break under a microscope, you might see "beach marks". These would indicate where the fracture started and in what direction it progressed.

Also, it might be interesting to see if corrosion was involved in the break - either where it initiated or as it progressed. If you hang on to it and run into a metallurgist, they could likely tell you a lot about how it happened.