Same thing happened to me a couple of weeks ago in an apartment block. Came out after a meeting got in the lift down to ground floor couldn't find the door I came in so I went out a different one found myself in an open air carpark at the back no way out electronic gates to the street, I thought oh shit. Then I saw a guy working in an apartment he let me back in. Turns out street exit and entrance was on the first floor. It would of helped if the lift was marked ground and lower ground. Bit of panic set in for a while 🤣🤣🤣🤣