That's pretty impressive...not so much that it started, I would expect that, but how quickly it did.

I used to start one without the block heater with temps in the low teens and high single digits pretty regularly, in MI...the trick was to give it some throttle while cranking and not let go of the key until it was really and properly running. If I let go the first time it fired it would stall and I'd have to start all over again. Sometimes it took a lot of cranking but it always started. 200K miles on that one.

I once rented an old Ford diesel U-Haul truck that I swear I cranked for 30 seconds straight before it fired...I was determined to crank it until it either started or the battery was dead.