There are doors


Darling
I tried to say good-bye last night, but you wouldn't listen. I'm not a coward, really I'm not.
If it weren't for the doors I wouldn't tell you a thing―that would be the best way. You may see one, perhaps more than one, at least a little while. It will be closed all around. (They must be closed on all sides.) It may be a real door, or just something like a guy-wire supporting a phone pole, or an arch in a garden. Whatever it is, it will look significant.
Please read carefully. Please remember everything I'm saying. You must not go through.
If you go through before you realize it, don't turn around. If you do, it will be gone. Walk backward at once.
— Lara
PS:  You always put these on, don't you? At the end. At the end, I loved you. I really did. (Do.)
Lara Morgan's note left on the kitchen table to Green, in There are Doors by Gene Wolfe.