Occasionally non warming up car is fine, but usually 1 min warm up is all you need than 5 mis.
Secondly loud noise could be as you were in D and still moving and shifted to R so gear cried loudly as it supposed to be stop completely before shifting to R, as in D and R gear works exact opposite direction and it need to stop at zero kmph and then switch to other direction.
Hope you havent broken anything, if car is doing fine just forget about it and avoid such rush shifting in future.