Biomedical Engineers (BMEs) can do many many many different things. It depends on your specific education and interests. BMEs can work at universities, hospitals, companies, non-profits and lots of other places. BMEs can work with medical devices, microscopes and movements of cells, robots, computers, patients, astronauts, and more! The real answer to your question is what do you want to DO, not what do you want to BE. If you like technology and want to use technology to enable people do things they might not be able to do without it, then someone might call you a biomedical engineer!