Why is their heart pounding?

In this snippet, Emilio is reacting to some news:

"We’re checking the carpark footage right now for it. Wait a moment – they’ve found something."

Everyone held their breath. Emilio’s heart pounded. Don’t pin your hopes on this, he told himself.

Again there is no connector. We infer the connection because we understand that what it's like to have hopes or expectations and for someone else to tease that they might be about to be fulfilled.

But this also means we could change either cause or effect and get a different scene:

"We’re checking the carpark footage right now for it. Wait a moment – they’ve found something."

Elena put a blueberry muffin in the microwave while she waited for Steve to come back to the phone. It was probably raccoons again.

"Tom, I have a letter from the police force."

Everyone held their breath. Tom's heart pounded. Don’t pin your hopes on this, he told himself.

You try. Copy the original snippet to the textbox below and change the cause or the effect.

Here's the text for you to copy:

"We’re checking the carpark footage right now for it. Wait a moment – they’ve found something."

Everyone held their breath. Emilio’s heart pounded. Don’t pin your hopes on this, he told himself.

Copy and paste the snippet, then change either the cause or the effect.