"요리사가 술집에서 맥주를 시켜요."
Translation:The cook orders beer at the bar.
"The cook at a bar orders beer" would be "술집에 있는 요리사가 맥주를 시켜요"
And that would be paying more attention to specifying which cook orders the beer. Which is not what the actual sentence is doing.
The actual sentence suggests that the listener already knows the cook being talked about. And there's no need to specify that it's "the cook at the bar" who orders the beer.
The actual sentence: "요리사가 술집에서 맥주를 시켜요" pays more attention to what the cook does than which cook is being talked about. Because it is presumed that the speaker already knows which cook is being talked about.
I hope this will help. I don't know how to explain further.
I was wondering that too. I found this Reddit post which I'll link after I paraphrase the explanation. Basically 시키다 covers more than just ordering food, and has a more authoritative tone to it, sort of like "to command". 주문하다 is more likely the one you would use for food as a customer, not 시키다. So it could be that the cook is ordering in a professional context? Idk exactly why a cook would personally be ordering for a beer from a bar but hey man idk all that cooks do https://www.reddit.com/r/Korean/comments/24izo6/difference_between_주문하다_and_시키다/?utm_medium=android_app&utm_source=share
But pubs serve meals, yeah? Does a bar serve a meal? Before I was of legal drinking age, I went to pubs for lunches and dinners, but I did not go to bars ever. Idk if it makes a diference what country you are from though (e.g. the US and the UK may have different definitions/nuances. I have both those countries in my background but still idk). It's also worth noting that 술집 literally could mean "alcohol house", so to me bar is much closer than pub, bc a bar is where I would go to drink, but I might go to a pub for a meal AND a drink