You don't fully understand what this machine does, and it did say you could transform anyone, so you don't see why you wouldn't want to play it safe the first time
Carefully climbing the staircase back into your bedroom, you think about who you want to test the machine on. Since you're not entirely sure what it does, you also think about whether or not to tell the person what they'd be getting themselves into. You quietly close the bookshelf behind you until it clicks, and replace the book upside-down on the shelf so you can find the button again
Turning back to your room, you sit on the edge of the bed for a moment and consider who you might want to put in a pod. Your mind has already decided that you will ask them for a random someone they like before even bringing them to the machine, so you have a way to let them decide what happens to them. After a few minutes, the one person that comes to mind the most prevalently is...