Scrappy

Correction: In order for the Doorbell Tape to work, he would have recorded the same message clips over and over again on the same tape, as no rewind feature would be available without someone there to rewind it manually. Since he recorded it more than once on the same tape, the next series of clips you hear should differ slightly as we hear, due in part to the fact that it's not the same clip as heard earlier. As such, continuity is not a factor, and no mistake is made.

Jazetopher