Got stuck at the end of a quest "Speaking With Silence".

[pesik]

At the end of this quest after Mercer opened a Nordic puzzle door i coming in the next room and get a message about a quest part "Find Karliah" was complited, then Mercer come in after me and stops on the stairways. And nothing more happens! I guess on that point it supposed to be a cutscene, where Karliah shots me with a poisoned arrow, but it just not happen! Could you help me please with a tips how could i fix it.
p.s. Although quest part "Find Karliah" is marked as finished in quest journal, but i get not any further part of that quest. But the quest itself still hanging as active.

[Mattbott]

http://www.uesp.net/wiki/Skyrim:Speaking_With_Silence

^^have a look at the bugs section at the bottom of the page, there are a few bugs associated with the puzzle door

Good Luck !

[PandaPo]

Try reloading an earlier save?

[likelolwhat]

Well, if you're on PC you can always advance the quest yourself, though it can be dangerous so keep a save as backup.