I have been exposed to hospitals as a guy who worked on their software, as a friend to a doctor, and as the relative of a patient. What I have seen is that hospital staff are generally well intentioned but extremely overworked, to the point that they can overlook obvious signs of a life-threatening illness. You can't just assume that if you're in a hospital then you'll be taken care of. The doctor can be too busy to pay attention to you or too tired to think clearly about your condition. The doctor might even just forget that you're there. You have to make sure that you're getting a doctor's attention, even if that means acting in a way that makes you feel like an entitled jerk.

My grandmother went to the hospital a couple of years ago because every few hours her heart would stop for several seconds. After she was in the emergency room for a day without receiving any treatment, some hospital employee came and wanted to discharge her. She and I refused so she ended up in a hospital bed for a couple of days, still with no treatment. Finally my sister came from another state, and my sister is less shy than I am. She actually found the cardiologist and made sure he looked at my grandmother's condition. Once he did, he immediately sent her to surgery. She had a pacemaker put in and recovered.

(In case anyone is curious, my grandma says that when her heart stopped for long enough that she lost consciousness, she felt a wave of heat go through her body, her vision faded to black, and then she passed out. It didn't hurt. In her case, her heart started again on its own but I suppose that for someone less fortunate, that would have been what it felt like to die.)