...instead of just walking around the corner...

The message is left in symbolic ("phoney") form rather than being delivered directly. Why is this, if (as Jung believed) the dream is indeed a message and not an attempted disguise of latent dream thoughts? Why does the mind wrap the message in symbols if it is not trying to hide its meaning? Why doesn't it just come out and say it?

Well, if C- gets the message (understands the underlying meaning), it will make her nervous. This would seem to support Freud's view that the latent dream content is disguised so as not to upset the dreamer's fragile ego.

But the other part of the answer seems to be that all thought is symbolic, and the dream is simply a direct expression of thought as it exists at the time of dreaming.

During sleep, the mind is lazier and less directed; the arrangement of thoughts is looser, less well organized. The mind is too tired to walk around the corner to deliver a message. One symbol, such as "the mind," is replaced by another which is stored nearby and with which it is easily confused, "the library". Thoughts lazily drift onto side tracks and become expressed by ideas which are less and less closely related.