When Klaus told his mom to get ready, he had already spotted the assassin who was sent to kill Jane; however, he pretended he hadn't seen him.
So he allowed him to gain the confidence to approach the pagoda.
Of course, if only he knew Jane was the most protected warrior on the battlefield, he would have had second thoughts. However, he moved forward, and Klaus allowed him.
However, just when he was finally free of the battlefield and ready to get into a strike range, he was sent away to space, where his body was vaporized.
Klaus' mom was already alerted by her son, who had countermeasures in place to automatically teleport any body he had given his permission to approach Jane.
Even the beautiful Jane had no idea she was targeted. Unlike Klaus, she doesn't have a hivemind that can allow her to do two things at the same time.
