Rear Wheels Locked New 2013 Outlander sport LE
 

So i live in a VERY cold climate. I took my LE for a car wash to get salt & snow build up removed (underneath and around wheels) with high pressure washer, took it home & parked in (unheated) garage.
Next morning had an emergency to go to, got in put in reverse & rear tires WOULD NOT move! I NEVER had a problem like this with my other (much older) vehicles. I continued to accelerate ALOT, spinning the front wheels until the FWD literally PUSHED the car out of the garage. Lots of front spinning of front tires. Then, in drive, the same thing! Rear tires still seized up as if the rear brakes were locked up? On the advise of an observing neighbor, (ididnt realize the rear tires were NOT turning) he advised to alternate drive/reverse gently, and they will unlock..which thankfully they eventually did and I was on my way to my 911!
MY QUESTION: in my PANIC to move, could I have damaged anything by continued rear acceleration and basically using the front wheel drive to force the car to move in reverse, and then forward (dragging the rear wheels)?
Again, this is a new vehicle and I have NEVER had this happen with any other vehicle after washing it down and parking it for the night.
Sorry this is so long, but I need reassurance I didn't harm my new baby ) -;