Scored Main Cap Bearing - Ouch

I would check the other main bearings, a few of the rods bearing , and #8 rod bearing. This is to try to determine if the debris is general or localized.

If it is just in this #5 main, then it may have just been a chunk of debris in that oil passage, which IIRC is separate from the main oil gallery that feeds 1-4, and the lifters and heads.

That is not horrible scoring, not great but not horrible IMHO... and is not all across the bearing, so not likely to be a bent crank. The wear in front of and behind the scored area looks pretty typical. Could you take a pix of the main journal and post it here?