I think the mock exit door would only be interesting with the corresponding emergency slide. The only problem is that in almost all cases where the emergency slide has been deployed and used, at least some passengers have been injured beyond a minor scrape - think severe sprains and tears, a broken bone, etc.

The purpose of the slide is to 1) empty the plane _very_ quickly 2) without causing a life threatening injury. Most people are not going to be injured using it, but some will and it's not really worth the small chance your leg gets fucked up forever from being ejected the wrong way.