Elysium would never think such thoughts, of course. He even felt that Leonel's actions were very stupid and only proved that he was far too weak. Why else would he be throwing such a tantrum?
In Elysium's opinion, Leonel had certainly felt threatened by his leaving without a word, and this was how he was venting his hatred. It was made only clearer by the fact he was only targeting the Owlans now, when before he had been slaughtering the Fallen God Beasts.
Maybe knowing that he was going to die anyway, he decided to try to deal the Owlans a blow in any way he could.
It was working, because unfortunately there was little Elysium could do. Even if he went, they would just end up in the same stalemate. Then would he have to leave without a word again? And then what?