As you walk back to the stairwell, you realise that the landing is wet. There’s water pouring out from around the lift doors, and you hurry back around to the door only to meet another mini-wave coming to meet you. You’re on the first floor. There’s no way it could have reached this high up. Yet when you open the door, you see that the water is still welling up from below.
As you stand there, dumbfounded, the water tops your shoes and makes its inexorable way up your legs.