Found this purely by accident and didn't screenshot because i was kinda tied up with healing on our first kill.
Our mage had spec'd fire for Lich King but forgot to glyph Blast Wave. When he used it at the transition to Valkyr phase [phase 2 or 3 depending on how you look at it], it knocked 1 of the Raging Spirits off the Throne.
It turned up again about a minute later but we'd been ready for it just in case it did come back. Basically you can throw stuff off the platform to increase dps uptime on Lich King and deal with mobs when they come back later.
I'm not sure how useful this will be but i'm sure there could be a use for heroic mode where the enrage timers are tight. Possibly having a dps on the edge in p3/5 to knock mobs of continuously.
As mentioned earlier i didnt have time to screenshot it as it was our first kill of the Lich King and was kinda pre-occupied. Therefore if you want photographic proof i can only suggest trying it yourself or waiting a few days til reset when i can take a pic of it.
Good luck on Lich King, hope you find a use for this.