A third person singular of phrase with fire

Question

Sentence: You see a car in the street fire two shots at the person, who was standing on the sidewalk. Source: *One man shot and killed during gathering of Trump supporter It seems like a car is a third person singular of phrase, but fire isn't fires. Is it correct? Why is it happen?

Answer 1

The quote is from speech in an interview, and the speaker isn't speaking carefully. As the comment points out, cars don't fire shots. The expression should have been

You see someone in a car fire two shots at the person...

That said, the question is the same. "Someone" is a third-person singular noun. Why isn't the verb "fires"?

Let's simplify the example:

He saw someone fire a shot.

The words "someone fire a shot" form a bare infinitival clause. It is the complement (object) of the verb "saw". That kind of clause uses the bare form of the verb, that is, the verb has no inflection for tense or number, and it is not preceded by "to".

This kind of clause is mentioned here:
Wikipedia "infinitive"

The bare infinitive form is a complement of the dummy auxiliary do, most modal auxiliary verbs, verbs of perception like see, watch and hear (after a direct object), and the verbs of permission or causation make, bid, let, and have (also after a direct object).

Here are some other examples of verbs of perception followed by infinitival clauses:
I heard her come through the door.
I saw him drive the car away.
I watched the building crumble in the earthquake.