Would Castrol Synthetic 20W50 oil kill and engine. Even if an oil change was immediately done a day or two after. The only driving that was done was to get back home approximately 5 to 10 miles and then another to 1000 feet to a garage the next day.
With such little information to go on it's doubtful the brand or viscosity you mentioned would cause a problem. We don't know what happened, what the symptoms are, which engine you have, or why you're blaming the oil.