Is that hidden boss by any chance "ISS-994 Power Droid"? I ask this because he drops this awesome looking (hooded) robe for Consulars (http://www.torhead.com/item/dBOh6h6/esseles-consulars-robe)
Was planning to solo Esseles this evening to get that, but if you need two people to access him...
Bit off-topic, but if anyone knows about any other hooded robes (light armor) don't hesitate to let me know.