Seems like a lack of experience if you've never seen a cracked liner. Bet you have never seen a hose pop either from a failed headgasket. The name tool fits you well.Hold on, i do have a comment;
Let's reverse engineer this mysterious engine failure you're referring to. I'm not suggesting this was the real sequence of events, but it makes better sense to me.
Let's pretend the truck was driving down the road and ran over a large widget... this widget then became an under-chassis projectile and struck, then busted the radiator tank... the cooling system excreted all of its fluids onto the road... the cylinder overheated and scuffed the liner... and then the liner cracked open before the engine seized ...or the driver noticed the severe, HEAVY engine knock.
...just thinking out loud.