Sorry, I’m reading on kindle reader and don’t have the printed page number.
In Chapter 7, Sending Messages of Intent - Receiving Messages and Moving, the code example runs the collision system after moving the player but not after moving the monsters. (The online example code shows the same thing. However, in the last paragraph before the wrap up for this section it says
Run the program now, and you have a turn-based Dungeon Crawler. You move— or press another key to wait— and then the monsters move. If they move into you— or you move into them— they are destroyed.
These seem to contradict each other. When a monster moves into you it does not trigger a collision and destroy the monster.