There's this dialogue here: (3:20) https://www.youtube.com/watch?v=yelfxueMlvc
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?