Robert,
I have not played the game but from reading the walkthrough:
Playback the audio recording Dave made the previous day, which will be listed in the PDA according to when it occurred, not when it was recorded by Dave ( here it would be 11/10, night, part one). Highlight the pertinent audio tape, and click on play, get the PDA off the screen by clicking on the round button, and click on the patient (same procedure throughout game).
So I presume, that you check the PDA and select the audio tape you want to play.
As for walking down the a hall - I presume that after the cutscene after playing the audio tape - you go to another cell.
Maybe a gamer that has played the game can verify this.