...school that's exploded when virus shielding is withdrawn (3)
I believe the answer is:
pod
'school' is the definition.
(I've seen this in other clues)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for pod that I've seen before include "Hull" , "Seed vessel" , "Long seed case" , "A pea grows in it" , "A seedcase; some whales" .)