A tape that plays by itself

Roger said to his wife: "Remember why do we come here. This is our best chance to get rich."

"Yeah, but... this place creeps me out. Should we book a nearby motel?"

"The letter has said that we must present to listen to Great Uncle's last will. It's a tradition to show respect to the dead and I think it's likely that is a condition to inherit."

"Ok, but where should we go? The letter said the event begins at 8:00 pm, in the conference room. It's already 7:50, and we still don't know where is it in this huge mansion."

Roger looks around and found a map on the wall.

"It's on the 2nd floor. Five minutes is enough. Go!"

Becky stares at the map and says: "Wait, there is something wrong with this map..."

"Come on, you're imagining things. This is a completely normal map."

"I don't mean the map itself, but the mansion... Wait a minute! Did you notice that there are too many bedrooms?"

She is right: the mansion has five floors, and in addition to the hall, the conference room, a kitchen room, a bathroom, and a restroom, every other rooms are the bedroom.

"Maybe... he invited many guests? Just ignore it, we have no time."

Running upstair, they quickly found the conference room. Roger pushes the door.

"No one is here."

"It's strange, at least there must be a lawyer... what is this?"

Roger sees a cassette deck on the table, and there is a cassette tape next to it. A note on the tape reads "My Last Will".

He places the tape into the cassette bay and closes it. However, before he touches the "Play" button, the tape starts to play by itself. A deep voice sounds from the cassette deck:

"Hello, my great-nephew Roger, and Becky..."