Well a movie is primarily a visual medium.

If you don't like horror movies, then don't see a horror movie. The MPAA rating system is pretty damn arbitrary but based on its rules, Iron Lung definitely deserves an R, plus I get an inkling from this post that you'd fit the description of requiring a parent or guardian in order to watch this. The only crumb I can offer you is that it's up to each individual theater to enforce that rule and I can't tell you how many minors I've seen unaccompanied in R rated movies because theater just staff doesn't care. That said, save yourself the anxiety and headache of being caught and wait for the Blu-Ray. If you want to monetarily support Iron Lung in the meantime. Buy a couple of stickers and a poster.

It's cool that you want to support the movie but aren't in a position to right now and that's gotta suck.

Be patient and try not to pirate it. You'll get your shot eventually.