こともあろうに

こともあろうに 【事もあろうに 】▸ 事もあろうに彼が約束を破るなんて I can't imagine how he would [should ] break his promise, of all things .▸ 事もあろうにどうしてあんなやつに頼んだんだ Why did you ask him a favor, of all people .