STUCK! - Later part of game

[StardogChampion]

I just got all my weapons taken from me and my grav gun can now kill humans. I've travelled forward a bit then gone up this small lift. There's a room with a force field and the lift can't go back down. I can pick up these energy ball thingies and fire them, but i've no idea what at. If I hold with right-click they sort of charge up.

What do I do?? I've tried firing balls at that thing in the far left but it does nothing. I've been bouncing balls all over the place... HELP.

 

[Jerklaren]

Pull the plug.

 

[StardogChampion]

I don't see a plug.

 

[StardogChampion]

There are 3 energy beams ahead that i'm taking the balls from. Someone told me I have to take 2 from each column or something, but it won't do anything. Does anyone have a walkthrough, I checked GameFAQs but I don't see one.