-
I'm dizzy. Needless to say, get off at the library gate. You said that in the library, the driver knew to get off at the library. For example, getting off at the next stop is a common example. Are you going to get off at the gate of the station, too?
The name of grounding gas after getting off the bus is used at, which is simply neither fish nor fowl.
Finally, if get to the library is more in line with the habits of foreigners, you can say get to the library when you take a taxi, and people will know. But I think you may be doing a test, and the test topic is the phrase get off, so just get off at the library.