on the fourth floor
Allora, che dobbiamo fare al quarto piano?
So, what should we do on the fourth floor?
— The Garden of Sinners Chapter 5: Paradox Paradigm (2008)
Però che stanno facendo al quarto piano?
But what are they doing on the fourth floor?
Stanno andando al quarto piano del parcheggio.
They're going to the fourth floor of the parking lot.
— Infernal Affairs (2002)