Instead of directly moving on, Lex studied the three dead assassins for a while. Their bodies did not disappear once the test concluded, so Lex had the opportunity to learn something from them, even if just a little.
With his left eye, he studied their bodies, looking for traces of abnormal laws while he used his hands to check their bodies for unusual muscle growth. He also searched for any treasures or items which may have had special effects. The fact that these assassins had been able to hide from him was not ordinary, especially since they were in the same realm as him.