Lots of premeds major in nonSTEM subjects. Major in whatever you like - just make sure you complete the pre-med requirements. Bioengineering? Often the harder road if you are trying to keep your GPA up and often it leaves little room to explore other areas, especially if you are also doing pre-med requirements. Doing engineering just to be sure you have a job? Not a good idea unless being an engineer sounds like what you’d enjoy doing. I suggest you go with the life sciences that you seem to like and resolve that you will probably need to get additional training - either graduate school or other certification if med school doesn’t work out. And remember that there are many medical industry jobs that don’t require you to be a doctor: public health, physicians assistant, health care management, epidemiology, to toss a few off the top of my head.