Lois knew she shouldn't be doing it, but she knew that breaking into Luthor's office was the easiest way to get the details she needed.
From previous dealings with metropolis's "most eligible bachelor" Lois knew that if he had something he wanted to hide, it would be somewhere in that office.
She waited until Lex was throwing a function downstairs in the building and used her press pass to get in. Once she was in the building it wasn't difficult to sneak away from the party and up to the top floor.
As she approached the door to the office she checked to make sure no one was watching, peered through the glass in the door and then tried the handle. When it moved downwards she briefly celebrated, glad for the lack of security, but not thinking too much of it.
She closed the door softly to avoid being heard and made her way over to the desk at the center of the office. She slowly and carfully looked through the drawers of Luthor's desk one by one. She was almost through them all with nothing to show for it other than notes on LexCorp's newest VR tech, which she resolved to scan over once she found what she was looking for.
After exhausting all of the drawers, she tried searching for any hidden compartments and sure enough she heard the classic telltale click of a catch coming undone. She found the panel that had popped free and tried to pull it free. It took a sharp tug to get it free, she looked inside to see a pile of ID documents. As soon as she did she noticed a faint hissing sound.
Looking round she saw smoke coming from the panel that she had removed. She felt the gas filling her lungs and the room span, then nothing. Everything faded as she collapsed in the middle of the office.