Learn Dutch: Ziet u waarom de conducteur nu snel door de trein loopt? - Do you see why the conductor is walking quickly through the train now?

This sentence perfectly shows the standard Dutch order for adverbs: Time, Manner, Place (TMP). nu (now) tells us the time, snel (quickly) tells us the manner, and door de trein (through the train) tells us the place.

Why is the verb loopt pushed to the very end of the sentence?

The word waarom (why) connects the two halves of the sentence and introduces a dependent clause (a sub-clause). In Dutch, a dependent clause pushes its conjugated verb to the very end, after all the Time, Manner, and Place information.

Wait, if the verb goes to the end, why does the sentence start with the verb Ziet?

The sentence actually has two parts. The first part, Ziet u, is the main clause. Because it is a yes/no question, the verb comes first. The rule about pushing verbs to the end only applies to the second part (the dependent clause starting with waarom).

Since the verb and subject are swapped in Ziet u, shouldn't the -t be dropped from the verb?

No, you only drop the -t ending in questions if the subject is the informal jij or je (like in Zie je). Because this sentence uses the formal u, the -t stays on the verb.