It's because battlefield trauma is pretty straight forward.  Stop bleeding, keep 'em breathing, pain control, get 'em on the bird.  Unfortunately normal medicine is now all about keeping the PT happy regardless of whether or not it's actually good for them.  Sally McButtertits doesn't want to walk around after surgery, ok, that's fine, anything to keep it happy.  Sally then throws a blood clot, it's the hospital's fault not lazy Sally.  Normal medicine is more negotiating landmines of speshul snowflake PTs so you don't get sued.  I never looked back after I got out.  I miss medicine sometimes, thoughr about getting my EMT license and then I remember I have to deal with the general public, and I go right back to my books.