2. Lois has just turned him down at the alter. That is humilitating for anyone. For him it is beyond that.
3. It is obvious that he has no clue he was really being investigated or that if he did that it had gotten far enough for an arrest warrant.
4. That they chose to arrest him in the middle of his wedding.
5. That he didn't have time to take care of Mrs. Cox. He says et tu Mrs. Cox. So he obviously knows she will turn states evidence, thereby betraying him.
6. Superman is locked in his basement and his biggest desire is to see Superman dead.
7. Then the final blow is when Superman has won yet again by escaping and Luthor is denied his "pound of flesh."
So instead of following any of his escape plans he takes a detour to the basement before doing anything else to kill Superman. I say BEFORE because when he finds him gone he goes back to his office to retrieve something. Why not get that first, kill Superman in the basement and leave through a basement escape route. I would feel that there is one there as well as any number of other places in the building.
So yes he would jump because ultimately he has had a break with reality and will not let lesser beings decide his fate. His HUGE EGO will not allow it.
