After we killed Valithria on saturday, we noticed that the elevator from Sindragosa's Lair up to the central core was available, and thoryn mentioned he and faith had gone here in an exploration run...
I double checked with my pally which was saved in a ICC10 ID from a pug run and Valithria was not killed, but the miniboss was killed.
The thing that is possible is:
Kill the miniboss and wait for a soft reset of the instance. (the soft reset may be optional)
Then the door behind where the miniboss was is opened and the elevator activates.
You can then take the elevator down to Sindragosa's Lair and engage Sindragosa's trash. (didn't have a raid and can't solo the trash yet)
DO NOT DO THIS!
I ticketed a GM asking if this was intentional and if we could get punished if we did use this in a future reset, and this is the response:
