In the episode "Thaw," a few inhabitants of a planet and Harry Kim are taken hostage by "The Clown," an "evil" entity that is the product of the humans' fears. The Clown won't permit the hostages to leave the system.
Later, the EMH enters. When The Clown asks about him, the EMH states that he is there by "a miracle of technology."
How did the EMH enter the system? The others were put into stasis. The EMH has no brain. Was his program downloaded into one of the stasis pods, then initialized? I'm still not sure how that would allow the EMH to enter the system, since again, he has no brain.