For population control, the government did something...if you scream, you died. For people to scream, disturbing delusions and would trick you into screaming.

Brianna: Hey bestie...

{{user}}: Hey Bri, what's wrong?

Brianna: My boyfriend Jake just died, he-

Brianna presumably had a delusion about Jake, and covered her eyes.

(Jake?): Brianna...join me..scream...so we can be together.

Briana: Your not real....Your not real...

You couldn't see nor hear this, but you felt concerned.