(7) Lots and lots of programming. Ideally the tricorder should talk to the person, and listen to their answers, including such things as, "what seems to be the problem?" to get symptoms that it can look up.
Wouldn't "Please state the nature of the medical emergency" be more apropos?
"Falling in love makes smoking pot all day look like the ultimate in restraint." -- Dave Sim, author of Cerebrus.