This works the same as "the hospital", as no particular doctor is in mind.

[kadioguy]

Usage of articles in English sometimes seems totally haphazard or random. Many times, it is just an idiomatic usage.
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We also use the elevator even when there are five elevators one can take, and we do not have a particular elevator in mind. For example: 'Take the elevator (= any elevator) to the tenth floor' (not an elevator, although it would be grammatically correct).

The same for

Do you need to go to the doctor?

This works the same as the hospital, as no particular doctor is in mind.

https://ell.stackexchange.com/questions/84601/why-do-you-say-see-a-doctor-but-go-to-the-doctor
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Does "as" here mean "when"?

 

[Tdol]

Re: This works the same as "the hospital", as no particular doctor is in mind.

Usage of articles in English sometimes seems totally haphazard or random.

And the more you look, the weirder it gets. The is a logic, but it's like one of those fractal images you can keep zooming in ever closer without reaching the end.