Spun bearings in these engines are common because the LIM gaskets are prone to failure and that lets coolant into the oil. Once the coolant gets in there, the lubrication breaks down and its all over.
In your case, it might have been no oil flow that caused the problem. When the oil pressure light comes on, it means you have less than 5psi which is basically no oil flowing. That could have been from oil being too cold and thick to flow. It doesn't take much time for a bearing to go with no lubrication at all.
I just had a problem where my timing cover was cracked on the inside (long story, my own fault for trying something stupid). The crack caused an internal leak that bled off oil pressure at idle. I only ran the engine for a few minutes, but when I dropped the pan, there were metal particles in there. My dumb mistake has me shopping for a new bottom end now.
