wèn lù shí shuō qīng zìjǐ zài jǐ hào kǒu duìfāng cáinéng pànduàn nǐ yào bú yào huí zhàn nèi huàn chūkǒu

问路时说清自己在几号口，对方才能判断你要不要回站内换出口。

When asking for directions, stating which exit you are at helps the other person determine if you need to go back into the station to find a different exit.