The Defector

Bring the Incriminating Envelope to Elementalist Ortell at the Outhose at the Forge of Supplication in Hyjal.

Stay your hand! Please, I beg you!

I'm only here because of a girl. Her words were so sweet... but now I realize the madness behind them.

Take this envelope. It has information that'll score you some points with your superiors.

The guards are distracted... I can make a run for it. Please. I don't want to die!

You will receive:

Apparently we're not the only ones conducting espionage here,. According to this letter one of your instructors has been involved with a remnant of the Cult of the Damned.

While killing Failed Supplicants for Spiritual Training: Mercy is for the Weak, Maurice offers this quest.

The ability to do this quest finishes after you turn in Twilight Riot, after which all the Twilight NPC's will turn hostile again. However, this quest appears to be optional and have no immediate follow-up.