Many medical devices run Linux. Most (AFAIK) patient monitors run Linux; GE and Philips (the biggest is business) both run on Linux. Those are the devices that keep you alive during surgery, make sure that those who are born too early (I don't know the English term here) are doing ok, monitor you state while you are in ambulance etc.
I'm reminded of a UAV doing the same thing. It ran L4 for low-level control, realtime scheduling, and security, and then virtualized Linux on top of that.
Sounds unbelievably clunky on the surface, then you realize it's a remarkably useful way to abstract everything cleanly.