What would cause something to break loose in an engine and come through the oil pan?

I was having other work done and the people who were repairing it said they took it for a test drive when they think it blew a rod. They said that they are not sure that it was a rod...but something in the engine blew out and came through the pan.What would cause something to break loose in an engine and come through the oil pan?
Usually a rod bolt or rod cap breaks first. Very seldom does a connecting rod break with not other causes except extreme high RPM usage or racing conditions. The causes may have been a spun rod or main bearing. Depending on the engine a timing chain or belt may have broken causing the pistons to smash against the valves.





Occasionally the oil pump fails and the motor starves for oil almost immediately wiping out the oil pressure. If the driver didn't happen to actually see the dash oil light come on that may have been what happened.





In my opinion in a perfect world the ignition should shut off when the oil pressure ever falls below a pre-set point. This would save a lot of motors.What would cause something to break loose in an engine and come through the oil pan?
heat, vibration, wear, time, lack of lubrication. etc





Many cases
the connecting rod came loose or broke and came through the oil pan.

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