Hydras in hooks

[contrapunctus-1]

I'm trying to implement a Hydra for an Elisp package, where I wanted a function calling the Hydra body to be placed in a hook. Unfortunately, it didn't work like I wanted - rather than waiting for the user to exit the Hydra, the hook functions after the Hydra were run right away. Is there some way I can make the Hydra 'block' until the user exits the Hydra?