I am half a person.

The darkest half. The half that isn’t quite 50 percent.

It’s time to check my fire alarm, so I stand up on my mattress and press the test button. It bleeps. I test it again because I read on Quora one time—a comment embedded deep inside a thread—that it’s possible to get a false positive.

Sometimes I feel like I am a false positive.

Not sometimes. For at least eighteen of the past twenty-two years. Since I was four years old. That’s when I realized two important things in life. First: there are no such things as identical twins. Second: the universe conspires to trip you up.

I test the alarm one more time and it bleeps.

I lie back down on the bed, and the four baby-safe pillows compress under the weight of my head. Pillows made with air holes. Breathable pillow slips. It’s rare that a full-grown adult woman suffocates from lying facedown in her sleep, but it is not impossible. There was a reported case in South Korea last year.

On my bedside table rests a knife with a three-inch blade. It’s legal because it does not lock and the blade is short, but I made sure to order the toughest knife available. It’s a balance of risks. Being incarcerated, even short-term, even just being questioned by the police, versus the risk of being violently attacked in my own home.

My entire existence is made up of balancing risks. KT, my twin, has never felt the need.