Here is my experience. Maybe the guidebook should be updated.
I paid for a ticked to the Residenz museum. I started the audio tour. After a few rooms I needed a bathroom. I continued. After 1/4 to 1/3 of the rooms I quit observing the rooms and listening to the tour. I started walking straight through just looking for a bathroom. I found one. Then an employee wouldn't let me walk backwards to the last room I observed so I could continue my tour. There are arrows pointing in which direction to go. They don't let you backwards. Then I figured that I could re-enter at the beginning. I found my way to the entrance. Being near the bag check desk, I decided thatbwould be a good time to get my string backpack back, go outside, eat something I had bought at a grocery store. Then I gave my bag back to the bag check guy, went to the entrance and showed my ticket. It was 11:50am. They wouldn't let me re-enter unless I bought a new ticket! The rules weren't written in any guidebook or website or sign i had seen. I didn't know that at this place, after you leave a room, they don't let you re-enter the room (you can't go backwards through the rooms) and you can't go back to the beginning and reenter on the same day.
I observed 1/4 to 1/3 of the rooms. I walked straight through the other rooms without observing them. I got screwed. Too late to worry about it now.