ABSTRACT
The unknown entry is referred to as the unknown because the first officer to enter the room moves directly toward the part of the room that was not seen (i.e., the blind corner) while slicing the pie (see Figure 4.1; see Chapter 2 for a discussion of slicing the pie). The second officer proceeds laterally into the room behind the first officer. It should be noted that while the second officer is moving into the room, he or she is not looking straight ahead; rather, the second officer looks first to the blind corner because that is the area of the room that has not been seen from the hallway.
