Now that new equipment is installed, you need to get a card in principle, but if you want to go in without a card, you'd better carry a schoolbag or take a glass of water and go in through the side door without looking at the security guard. If he asks about your card, you can say that it is upstairs and you forgot to take it off. You come out to get something. If you think it's still unreliable, I suggest you borrow a card from a friend who studied at Finance University, preferably the one you found after you lost it, as long as you can fool around, so it won't affect both parties.