Voice on the Radio talking to Patrick

Patrick gets bitten by the monster in the neck, disinfects the wound with alcohol and drinks some, and starts hearing the voice from the radio telling him something that only he, Patrick, knows - that there are neighbors and that he should kill the man and leave the girl. The voice messes with Patrick's mind, temping him to go berserk.

This was a very promising plot line which, unfortunately, turned out to be a dead end in the movie - the effect just disappeared and the voice didn't come back, only the voices of other survivors came in later.

What is the explanation for this mind controlling voice? Was it just the effect of alcohol combined with the delirium from infection (which he overcame without a trace)?

Did anyone get a feeling that the voice could have been so much more? I was getting excited about the possibility that the infection was taking over the victim's mind and could possibly connect the victim with other victims telepathically, building a network of controlled humans who look like humans (rather than monsters). This would have been an impressive adaptation for the virus as it would allow it to spread easier among the scarce population without being detected and survive longer.

I was expecting Patrick to either come to the side of the monsters and attack the house, or better yet, try to gain trust of John and Lu only to strike when they least expect it.

This would have been a thrilling continuation. Instead this voice incident didn't get any development and left me wondering what it was for at all.