mc will fail and die before he can touch the prime minister, his image will be slandered, because he has no political power, no allies, even his father the king ignore him. The fact that he only got poisoned food means the prime minister and his sycophants are just toying with him, they could have get him killed easily if they wanted to.Then kill the prime minister?
Like the country is already corrupt, what difference would it make to kill him?
inb4 he rescues a cute girl in a carriage being attacked by wolves