MelasZepheos said:
In the book, the comedian discovering the plan was an accident. In the movie, there was nothing for the comedian to accidentally discover.
The unreality of the squid, it's functionality, the island, the teleporter, and how everything would come together is what drove the comedian over the edge.
Except... in the movie, there was no island. There was no central staging point for Ozymandias' plan. There was just Manhattan and Ozy working on solving the energy crisis by duplicating manhattan's abilities. The only way the comedian could've known the plan is if ozy told him. Then why did he tell him? If ozy told the comedian, why did he wait to kill him?
Thus, gaping plot hole.