Would fighting/war be possible in a lucid dream, or would the excitement wake you up?

I'm interested to see if your pulse (as in your artery on the neck) would be any different, or off beat in a dream.

Is there any danger (psychologically speaking) in creating a sort of dream companion that is involved in every lucid dream? I ask this because I read about someone who did this and it ended up in a mental disorder and severe insomnia.