His storage area is in a cave high up a mountain somewhere to the south of the tower, I think: can't remember the exact location but it's not that far away from where you find Needleman. I recall climbing up to it prior to the fortresses arriving at which point the entrance is blocked by rubble but it should be clear from this point on.
As far as I know, the tower doors no longer open at this point in the game, though I could be wrong; and hopefully Raze can remember about the shield...
