The missing part of the explanation (imo), at least the part that helps me explain it in my own brain, is said but not explicit. Imagine the actual mechanics of Monty opening the doors, one by one, and when he gets to that 223,205 door as stated, he skips it, and keeps skipping it. Why _that_ door? What makes it special? I don't think expanding the number of doors without that bit of intuition gives you much.