I guess because the disturbing things you can find there, it was designed to be an 'optional' area from the start. If you turn it off, thus removing the main entrance, there isn't supposed to be any other way to get there.
I guess because the disturbing things you can find there, it was designed to be an 'optional' area from the start. If you turn it off, thus removing the main entrance, there isn't supposed to be any other way to get there.