[ERASER5]

The rod is definitely bent. You said "The piston clearly looks cracked" but I only see the crack in the cylinder wall. That very bad! As well as the source of water in the crank case.

If the #4 lifter froze due to lack of oil, that would hold the valve open, piston hits valve, crank keeps pushing the rod up, but the piston-valve interference stops the piston, so the rod bends. The side load force cracks the cylinder wall. Dead in 10 seconds. Of course there is more wrong here, like why there was a lack of oiling.