Could be, but it must have been done without the knowledge of the elders. Otherwise it would have been an easy thing for them to walk out at night, stake out the guard post and collect any med supplies needed when the guard went to the can. If it is possible to keep newspaper clippings and monster suits hidden yet available for use for ~20 years it is an easy matter to do the same with medical supplies. At the least they could easily be repackaged to appear to be from the town doctor.
This takes the discussion right back to the logical problems of this movie: The elders constructed an elaborate escape to form a society where they thought tragic death could be eliminated. They traded disease for murder yet failed to make adjustments when reasonable solutions were readily available and would preserve the village. It all comes back to M. Nite Shamalamadingdong and the writers IMO; they wanted to build a particular story with a particular twist and were quite willing to stand reason on its head to do so. That's why I think the film is lame. That was a lot of time and work to deliver a 1/2 hour Twilight Zone twist. Glad I paid the matinee price.
The same kind of contrived crap was poured on by the ocean full in "The Day After Tomorrow". The film was loaded up with stupid actions by people who know better stacked on top of wildly improbable events in order to deliver poorly contrived suspense scenes where I didn't care if they DID just go ahead and die. TDAT was just more heavy handed and obvious. At least the film had some good special effects.
I saw the faulty logic part of the character flaw within the elders. You said it best, the elders tried to create a society devoid of tragic death but ultimately failed to make adjustments inspite of a reasonable solution. Their failure to act was not a result of faulty logic but of hubris. Walker the elder swore and oath not to return to society. By sending his blind daughter, he kept his oath and because she was blind, her innocence was spared. Moreover, because she was attacked by one of the beast, her illusion was spared as well. As for the elders, they all chose to continue living as they had for the past 20 years, though I imagine with heavier hearts, knowing that they could have done more prevent illness and death all along.
I agree that for all intents and purposes this story would make a decent 1/2 Twilight Zone episode. Still, there was enough chills and suspenseful scenes for me to like the film, even without special effects. After reading so many posts here, I think it is a film worthy of discussion.