2.14.1  What happened to the flesh creature/doppleganger/Lara's
            Mirror creature?  It disappeared/stopped moving.

            This is a common problem when you spent too much time
            square dancing with the doppleganger.  It will stop
            responding to your actions, and if it disappears, you can
            usually look around and find that it has "died" and is
            lying in some corner somewhere.  This is clearly a bug,
            but the workaround is to go to the ramp that Lara
            initially slid down from, and take a standing jump back up
            the ramp and allow Lara to slide back down the ramp into
            the room.  This should reset or reactivate the
            doppleganger and you can continue.