U deset sati means “at 10 o’clock” – and consists entirely of building blocks you already have.
On the underground you eat a dessert without a radio and give a piece of it to the well-fed tiger. The underground gives you the u, the dessert gives you ten, the tiger gives you sati.
So that each word also works outside the sentence, both have an extra detail: on the underground you fall over, and the well-fed tiger wears a watch that shows when it gets fed again.