The thing just reached up into the chest cavity and gave a good tear.

That would be in the chest cavity, together with communication devices.

"I'm going to open up the chest cavity," she spoke into the mike.

The chest cavity was deformed as well, although we wouldn't know that until later.

At this point, shears are used to open the chest cavity.

I want to go into the chest cavity and look at the heart.

Now think of how these forces might affect the organs, especially those in the chest cavity.

It was as if a living thing were crawling about inside his chest cavity.

I also figure the heart was cut out by someone who knew his or her way around a chest cavity.

A good place to aim for is directly in the center of the chest cavity at its lowest point.