A very nice analysis; detailed and observant. But in ranvirs defence he has always hidden his pain for the sake of his family, especially Ragini. This can even be seen in the jail track when Ragini came to see him. He never wants to see ragini in pain, and he understands that ragini's happiness depends on his. From what I observed, he was trying to hold back alot of tears and pain. As for the wink, I thought it was a nice touch. It showed characteristics of the ranvir we know, who is a little cheeky and quite playful... i guess ironically even at the brink of death. But as they say 'old habits die hard'...
The whole episode was kind of desperate, trying hard to establish Anmol in Ranvir's place. We have seen Ranvir in past, and he is a good actor. In this scene, he is not definitely not good, and I agree that he seemed as if he was trying to stop himself from laughing. It seems like Kinsuk was not convinced that Ranvir is actually dying !!