There was obviously a problem that caused the (presumably) rod bearing lock up.
It was good that you got off with relatively minor damage.
Assuming the crank hadn’t been reground previously, that was most likely due to low oil pressure.
This may have been due to a pump problem, or more commonly due to wear of the centre mains.
When a triple crank is reground, it is essential that the centre main journals are ground using the outer main journals as the end centres (so all 4 mains are precisely Concentric
Using any other centres will not achieve this concentricity.
I only mention this, because a car crankshaft regrinder may not take this into consideration, as they will usually grind all main journals (including the outer main journals) using the end centres of the shaft.
In your case, they wouldn’t have reground the outer main journals.