Special Door, keeps out 343. 5016

SCP-343: I know. That's why I'm proposing a new method. So far we've been able, at most, to neutralize it long enough to move it. But once he's awake again, neither I nor the infrastructure at your Sites can keep him contained. That's why I'm proposing an alternative form of containment.
The Administrator: What kind of containment?
SCP-343: There's a prison he won't be able to escape from. We can lock him up in the world that you've opened with what you call SCP-004-07. If he breaks containment, we'll close the door. He won't be able to get through without a key.
The Administrator: A simple extra-dimensional lockdown? Couldn't you have suggested this earlier?
SCP-343: This is not a simple extra-dimensional lockdown. The door you open with these keys is not a simple door between dimensions, as the Wanderers's Library can be in its own way. It is much more than that. The reason I didn't suggest this earlier is because I was… forbidden to intervene on the other side of the door. It's already bad enough for me to come in here when I have nothing to do with it.
The Administrator: Forbidden? For what reason? What does that door mean to you?
SCP-343: There's no need to ask any more questions, Laura. You won't get any answers. Let's just focus on neutralizing it, shall we? Here's his current position. How long will it take Site-62 to be ready for him?
The Administrator: I'd say a little over a week.
SCP-343: Good. As soon as you're ready, let me know. I'll make my move then.