YES
should I add a ghast hiding up there as well?
no instead have a wave of trapped souls (skeletons) come up from tnt blasts in the floor,the spawners are revealed and they start attacking as you try to escape while lava comes down from the side of the castle because that's how liquid physics work in minecraft
like this
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\ <-- castle exit/enterance
-------------------------------- <-- floor
----------TNT------------------
--------------------------------
--------------------------------
---------Spawner------------
TNT explodes,spawner is revealed out of the ground,skeles start to spawn
might take some trial and error on seeing if the spawner explodes too