Hiding 3rd level menu from sidebar, but displaying elsewhere. Possible? - D7
The level of control you need can be achieved using Menu Block module:

So… have you ever used the Main and Secondary menu links feature on your theme and wondered “how the hell do I display any menu items deeper than that?”
Well, that’s what this module does. It provides configurable blocks of menu trees starting with any level of any menu. And more!
So if you’re only using your theme’s Main menu links feature, you can add and configure a “Main menu (levels 2+)” block. That block would appear once you were on one of the Main menu’s pages and would show the menu tree for the 2nd level (and deeper) of your Main menu and would expand as you traversed down the tree. You can also limit the depth of the menu’s tree (e.g. “Main menu (levels 2-3)”) and/or expand all the child sub-menus (e.g. “Main menu (expanded levels 2+)”).
Pretty simple, eh?