Love, don't be jealous

Riggs dragged Loki inside the seemingly normal resthouse while Jack languidly followed suit after he flicked his cigarette and stepped on it.

"What happened to them?" Wren questioned as he helped Rex to get up. Seeing that both Leon and Rex were a bloody mess, he was somewhat bewildered on what triggered Rex to do such a thing.

"The usual… he pulled him back." Tito briefly explicates which Wren instantly understood.

As stated, Leon was the most dangerous among them. Not because of his insane and unremorseful killing but when he gets so worked up, he also lose his conscious mind. Moreover, the scene when Dragon stole a kiss from Seraphina might have an added impact to trigger Leon.

Hence, the most capable person aside from Seraphina to get Leon back to his right mind would be Rex. After all, Rex wasn't as careless as Riggs and as skewed as Jack.