The Organization of Water had made no mistakes, but their enemies had surrounded them.
Many things in this world don't succeed simply because no mistakes were made. The Organization of Water hadn't erred, but neither had their enemies.
Nicholas's men gave Yang Yi no time to react, going from asking Steve a few simple questions to deciding to leave, all within less than ten minutes, but the enemies had already arrived.
The speed of the enemy's arrival was astonishing. If Nicholas had formed this team on the spur of the moment after learning of Deyo's death, it would have been impossible for them to surround Yang Yi so quickly.
The only explanation was Steve's words, that it wasn't just Big Ivan or Yang Yi who wanted Deyo dead, but Nicholas as well.
Moreover, Nicholas had likely planned this in advance; it was possible that Steve was actually Nicholas's spy.