Wow. Odd that you weren’t able to switch into park or reverse. I always that that was supposed to be the ultimate fallback. You need to just take it easy and enjoy life the rest of the day.
Many automatic transmissions have an interlock to prevent park or reverse from engaging when the vehicle is traveling forward with significant speed. Without such an interlock, the transmission would be ripped apart but wouldn't do much braking. Throwing the transmission into low gear and turning off the ignition would be more likely to help.