Die Hard was an inside job.
Who is the real winner in all of this?
Holly Gennaro.
How did Hans Gruber and his gang know that there were hundreds of millions in Bearer bonds in the safe? That wouldn't have been common knowledge. Only senior executives would have that knowledge. Holly was a senior executive.
Who was Holly? She was a super ambitious employee. She says so, she wanted her douchy bosses office. Is it any coincidence that the two people directly abve her were shot dead by the bad guys?
Why invited John McClean? They weren't getting on. He was her cover story. It couldn't be her that tipped off the bad guys? She invited her cop husband to the party.
Holly's grubby plan was to tip off the thieves of the loot in the safe in exchange for eliminating her rise to the top of the organisation.
She conned us all.