most doctors are unlikely to bring external flash systems to work and on-camera flash often results in poor clinical images due to either unwanted reflections, shadow from lens or over-exposure at macro distances, or just flat lighting.
unfortunately, the lighting sources in most EDs are quite variable in their colour temperature and the camera auto white balance or even presets can be very inaccurate in portraying the true skin colour.
furthermore most ED lighting is of “office level” illumination and you may be better suited to using a digital SLR to manage the lower light levels (eg. better image quality at ISO 400, image stabilisation for hand held images, better autofocus at low light and wider apertures to allow more light in).