The air shimmers around the edges of the of the orb, creating a halo of wisping shadows. The orb draws power from the the last two crystalline pillars expanding the halo. Octane and Paelis are at a loss to what the orb's purpose is, but it is clear that it is drawing energy from the surrounding area and that it is wise to leave the complex before the orb draws power from the teleporation runes, leaving you stranded in the Tower of Mysteries.
You search the southeast room and find various notes and books. You quickly round them up along with the crystal orb and move retreat to the second level. You quickly search the library on this level and find that every book you open has blank pages. You search the northwest room with the container with the Bronze Warder. You collect the notes from this room and exit the Tower of Mysteries.
You return to the Seven-Pillared Hall and inform Orontor of what had transpired in the Tower of Mysteries. He is very gracious that you defeated his former colleague, saving both the Seven-Pillared Hall and the Mages of Saruun. He asks for the notes and crystal orb to determine what Paldemar was up to.
Octane, Orontor, and Paelis scour the notes of Paldmar trying to determine what was the purpose of the orb. A cursory pass over Paldamar's notes reveal that contraption that contained the Bronze Warder head was an Infernal machine designed to steal control over the other Bronze Warders, giving Paldemar uncontested control of Thunderspire Mountain. The notes referred to the floating orb on the third level as a Shadow Engine. It was suppose to be the power source for the Infernal machine by drawing arcane energies from the Shadowfell.
From what you can tell from the notes, the Shadow Engine was not fully complete. You surmise, and a quick visit back to the Tower of Mysteries confirms, that when Paldemar activated it, the portal it opened to the Shadowfell was not fully contained within the Shadow Engine. Orontor believes that it is weakening the veil between the worlds as it is drawing energies from both. The Shadow Engine was not designed to store the amount of arcane energy that is being drawn from both realms and will eventually explode shattering the veil between the worlds plunging all of Thunderspire Mountain, and possibly a large part of Nentir Vale, into the Shadowfell. Unfortunately neither you nor Orontor can figure out how to shutdown the Shadow Engine.
Paldemar's notes contained parts of an ancient scroll that the Shadow Engine was based off of. Orontor believes that the scroll was from the Tyrenil Empire, a civilization that predated even Arkhosia and Bael Turath. He suggests that finding more information about these scrolls is the only way to stop the Shadow Engine from destroying Nentir Vale.
Orontor says, "I will recall the Mages of Saruun and we shall try to contain the rift and find a way to shutdown the Shadow Engine. I ask that you find any information you can about the scrolls. What remains of the last great empire, Nerath, lies to the east of the Dawnforge Mountains. The captial city, Astoria, contains the Great Library of Nerath. That is a likely place as any to start trying to find out about the origin of the scrolls. I warn you though, do not speak of what is happening here in the Thunderspire to any you do not trust. This was a temple of Shar and if her agents or spies learn what transpired in the Tower of Mysteries, they may try to hasten the Shadow Engine tearing apart Nentir Vale."