In instance Acquisition: select and Hail the wall to rotate it revealing a sarcophagus behind. Sarcophagus is breakable. Contains corpse of one of the D'Mortes, perhaps the one Izinar is trying to raise. It's possible to get behind the wall through persistence and bad timing while hailing the wall, and just as impossible to get back out, so have a recall spell ready.
Watching the Watchers quest.
This is the 1st Sarcophagus.
If on the quest Watching the Watchers, level 40 ^^^ Master Slayer Varash spawns and attacks. Kill him for update.
Watching the Watchers quest.
This is the 2nd Sarcophagus.
If on the quest Watching the Watchers, level 40 ^^^ Archkeeper Feras D'Lorn spawns and attacks. Kill him for update.
Watching the Watchers quest.
This is the 3rd Sarcophagus.
If on the quest Watching the Watchers, level 40 ^^^ Nightcaptain Revelaz spawns and attacks. Kill him for update.