It IS possible to make it open slow and close fast, just make the animations different speed. IIRC, you specify the length of the animations when adding the door. And I believe there's something to do with collision meshes in the new JVS doors version, since the vault and manhole doors both use them.
You really should make a portcullis and some proper fortress doors (cathedral doors, or like the doors from
this - probably the latter so there's no frame stuck on)
