+Александр

Thank you both!

You're welcome! Но "в одном магазине" значит "в каком-то"

I thought it meant in the same store.

Не согласен с Еленой! От контекста зависит и первое что в голову приходит здесь - одинаковый магазин.

If it were "in the same store", то было бы "в один и тот же".
Here, since only one shop is mentioned it also means "the same".
We often use "один" meaning "какой-то, некий". Например:
Я сейчас читаю одну интересную книгу. Я поехал в один магазин, но там этой детали не оказалось. В один прекрасный день я поеду на море.

Тут как бы противопоставление идет. В смысле - их двое, а работают в одном месте.

Я согласен - в один и тот же магазин.

Well in the story I’m reading, the fact is that they worked at the same store. But aside from that, I’m sure I’ve seen они учились в одной школе before, meaning the same school. Why wouldn’t that apply here?

And I’m not arguing with you, I’m just curious.

"Why wouldn’t that apply here? " - I don't understand the question

I think the meaning can be ambiguous here

If одной means “the same” in одной школе, why wouldn’t that apply to один магазин as well?

apply = be true for

I can explain only how I feel. Они учились в одной школе - it's a long period in their life and that's why the same school is meant.
Они устроились в один магазин - it's an action and as I understood the main idea is that they found a job (no matter where, just in some store). If I wanted to stress that they found the job in the same store I'd say "в один и тот же магазин". I agree, the context is important.

Thank you. So if they found an apartment together, could you say переехали в одну квартиру? or is that also too short term?

Here I'd say "переехали в одну квартиру".
But:. Они переехали в одну квартиру, но она оказалась неуютной. They moved to an apartment, but it turned out to be not cosy". Here the accent is on the fact that they moved to some apartment (it also means that they moved together, but this is not the most important information here). So, it depends on the accent, what part of information is more important, I guess.

Thank you, now I’m not so confused. But yes, in the story, the two young men worked in the same store together.

You're welcome, Uly! So, what we have is that the meaning of один may be "some" and "the same". And the translation depends on the context)

Great 👍🏼