I agree with what everyone else said. I don't think it's a good idea to put too much emphasis on personality... That said, I do think somethings come more naturally for certain personality types. For example, psych came very naturally to me, which is consistent with my personality type. BUT, I wouldn't do psych because I just don't like it as much. So, the most important thing is do what you enjoy and can reasonably learn to do well (with time.)
INTJ is a type that is supposedly the sharpest, the most academic in nature. So, even if it doesn't come naturally to you, I'm sure you would be able to be a good EM doc with training.
The ideal personality for EM would be ESTJ or ENTP.