Shannon's forward armour left a shell trap

Did HMS Shannon's armour create a shell trap and leave the rest of the ship exposed?

Yes; the armour covered a limited forward target while fragments, side guns, and lightly protected structure remained serious vulnerabilities.

The viewer points out that fragments striking the armoured face still needed somewhere to go and that an enemy could hit the unprotected structure around it. Shannon's armour concentrated protection on the forward target presented during her intended attack. Side guns, surrounding structure, and much of the hull remained exposed to off-angle fire. Even a hit on the armour could throw dangerous fragments into adjacent spaces. Shannon was a ship of contradictions: the protection served a narrow tactical idea while leaving much of the fighting ship vulnerable.