Japanese by Example
Learning through examples in manga

Indiscriminate murder would be one thing if with 〜ならともかく

名探偵コナン » Volume 5 » Page 110

Sonoko is invited to a band’s after party. During the get-together, the band’s singer Tatsuya eats a rice ball only to collapse and die. The police are called in, and Inspector Megure discovers the victim was poisoned. He accuses the man who prepared the food, but Conan bites into a rice ball to show it’s safe. The victim’s manager, Mari, agrees.

麻理(まり):
無差別(むさべつ)殺人(さつじん)ならともかく、たまたま達也(たつや)()べたオニギリだけに、あらかじめ(どく)仕込(しこ)むのは不可能(ふかのう)じゃありません?」
“If it were indiscriminate murder, that's one thing but since it was just the rice ball Tatsuya happened to eat, wouldn't it be impossible to poison it beforehand?”
目暮(めぐれ):
「た、(たし)かにそうだが…」
“Th-that's true.”

The grammar ならともかく conveys that poisoning one rice ball is reasonable in the case of indiscriminate murder, but it’s an unreasonable method for a targeted murder.