Can someone rephrase the final trick by which he learned the last two numbers? Whuh huh?

If you look mischievous up in the dictionary you will find the picture of Feynman @5:50 in this video. True story.

From Surely You're Joking, Mr. Feynman!:

"When the lock is opened and the drawer has been pulled out and the wheel is left on ten (which is what people do when they've opened their filing cabinet and are taking papers out of it), the bolt is down. Now what does that mean, the bolt is still down? It means the bolt is in the slot made by the three discs, which are still properly lined up. Ahhhh!

"Now, if I turn the wheel away from ten a little bit, the bolt comes up; if I immediately go back to ten, the bolt goes back down again, because I haven't yet disturbed the slot. If I keep going away from ten in steps of five, at some point the bolt won't go back down when I go back to ten: the slot has just been disturbed. The number just before, which still let the bolt go down, is the last number of the combination!

"I realized that I could do the same thing to find the second number: As soon as I know the last number, I can turn the wheel around the other way and again, in lumps of five, push the second disc bit by bit until the bolt doesn't go down. The number just before would be the second number.

...

"In this way I picked off the last two numbers of various filing cabinets. When I got back to my office I would write the two numbers down on a piece of paper that I kept inside the lock of my filing cabinet."

It's a fantastic book, as is What do you care what other people think? Highly recommend.

The video didn't really explain that very well did it? As much as i love Numberphile I feel sometimes the videos gloss over important detail.