There's this dialogue here: (3:20) https://www.youtube.com/watch?v=yelfxueMlvc
- 请问,洗手间在哪里?
- 洗手间?在那边。在那里的右手边。
- 哦,好。我知道。谢谢.
- 不客气,应该的。
So... "我知道" certainly doesn't mean "I know" here. Because if he had known, he wouldn't have asked. So what's the meaning? And my second doubt is about "应该的". It's the first time I hear it and none of my dictionaries gives a translation which would make sense to me here. What is it?