If the defrost is broken(sounds like it is), there will be a lot of water when the ice melts. I fixed my own fridge defrost and it was pretty easy except I failed to anticipate all the water and it left an alarmingly large puddle. It was also pretty gross since there was a lot of crumbs and dust bunnies under there.
The odd thing is that I haven’t turned off my fridge yet, but I’ve had to mop up water multiple times a day sometimes. I’m guessing I’ll unplug in about 4-5 days.