The first thing that would come to anyone's mind when exploring an old, abandoned, underground temple would be traps. Anyone who had seen any movie ever would know to expect traps.
Why would there be traps, and why would they work hundreds of even thousands of years after being made, Lex could not guess. But he was not looking forward to being impaled by a row of spikes, or run over by a massive boulder - no matter what the excited expression on his face may seem to indicate.
Lex also did not pull out a hat that looked eerily similar to the hat of an iconic movie figure who was both an archeologist and a treasure hunter.
To no surprise, Lex immediately discovered that there really were traps in the tunnels. However, unfortunately- eh, no, fortunately, Lex was both too powerful to be affected by them, and too sharp to fall to them.