@hayhor You can throw it from anywhere inside the pylon, as long as (a. You aren't on the edge of it's effective area, (it seems like a bug) and (b it won't land back inside of the effective area.
It might be easier to do depending on the position of the ult, (do walls and stuff restrict the effective area? I think it at least affects the shield charge, because there is/was a bug where bangalore smoke would prevent the pylon from recharging shields.)