Time travel and parallel worlds...

I'm almost entirely certain that this morning's dream was inspired by the latest episode of Doctor Who... but that's ok.

I should have written this down just after waking.  Now it's just fragments.

There was a basement workshop (I didn't recognize the place).  In it, there was a large machine that could open up portals to other times and other places.  A group of us had snuck in to use it to fix the past somehow.  I remember I was trying to save someone.  It needed one person to reset the breakers and another to throw the recall lever that would reopen the wormhole and allow us to return.  I think it also needed something from that time to allow it to properly "aim".