Breathe Deep into Your End, Experiment

You've been my captive little lab rat for several years. You been locked away in my secret compound, subject to my whims and experiments. It's a sad day for you, because today is our last day together. You see, I've done everything I can possibly do to you. You're not much more than a sentient vegetable. I'm going to get rid of you and replace you with a new toy to play with. That means I have to put you down. You've been such a good lab rat for me, I've decided to reward you by doing it slow and painless. A little injection will stop your heart and a little gas will put you to rest for good! Breathe deeply, little experiment...