In the story I'm still storyboarding, a secondary antagonist attempts uses a control panel to lock away some of the good guys in a room and then attempts to pump in carbon monoxide. When the primary protagonist finds and attempts to stop him, he, in desperation, shuts the lid to the control panel and swallows the key. They scuffle, the protagonist wins and attempts to pry the control panel open, but needs the key. Yeah, I'm sure by now you know where this is going. So my question is, what precautions would one have to take before cutting open the human stomach? Would you have to cut it open and let the hydrochloric acid drain out first? How would you drain it if that's the case? Would a metal key survive the stomach enviroment, even for just a short while? Can you even dissect a human being with only a kitchen knife (the intended implement of death)? If anyone can answer these questions or direct me to somewhere that can give me answers, I'd truly appreciate it.