Gao Guang didn't intend to introduce Leaf to Otto, so he didn't answer Leaf's questions.
But this choice was obviously a mistake, because Leaf became increasingly curious about Gao Guang, his teacher, and even began to admire him because of his curiosity.
Gao Guang could sense the psychological change in Leaf, which just made him even more irritated.
Why should an old scumbag who is fickle and sponges off women be admired by the KGB's first operative?
So when Otto came to visit Gao Guang the next day, Gao Guang just wanted to shatter Leaf's illusions about Otto as quickly as possible.
Familiarity breeds contempt, right? Once Leaf got to know Otto and found out what he was really like, he should give up his fantasies.
Otto and Heidi stood at Gao Guang's bedside, who had just finished plastic surgery and was still covered with gauze on his nose, making him actually look quite clownish.