Ok but please give us the essay about Tintin's belief (and defensive mechanism I dare to say) that he and his friends are invincible!!!
Ok so, throughout the albums, Tintin operates on this naive belief that nothing bad will ever happen to him and his friends. And technically, he’s not wrong, because comic book logic, but it nonetheless influences how he behaves in his adventures.
The belief primarily comes from the fact that he’s always escaping dangerous situations relatively unscathed: murder and execution attempts, kidnappings, getting drugged, etc. No matter what happens to him, he’s always fine in the end, and that’s what convinces him that nothing truly bad can happen to him.
But he doesn’t just believe this applies to him; we see him apply this same logic to his friends. After all, they all get out of the same situations as unscathed as him. And as a result, Tintin is constantly throwing himself and others into danger with little thought about consequences, and often, he does so despite complaints from Haddock, who is a bit more realistic about the threats they face.
Tintin in Tibet is an example of this: no matter how dangerous the situation is, Tintin doesn’t stop to consider the consequences until it’s almost too late. It’s worth noting that he doesn’t exactly pressure Haddock into going, but simply assumes (correctly) that Haddock will come along and as a result, is never truly surprised when Haddock shows up. The one exception to this is the time he manipulates Haddock into continuing the search after Tharkey leaves (which I'll come back to).
Another example of this attitude is in Red Sea Sharks. Despite knowing how dangerous the situation in Khemed is, and the fact that the emir doesn’t outright ask for help, Tintin suggests they head there without really stopping to think about the dangers they might face, and once again Haddock follows reluctantly.
This belief in his and his friends’ invincibility also influences how Tintin behaves in dangerous situations. In The Crab with the Golden Claws, Tintin remains optimistic when he and Haddock are stuck in the desert, despite there being no indication that they might be saved. Unlike Haddock, he doesn’t truly believe they’ll die, and that’s what allows him to push forward. In Red Sea Sharks, Tintin remains calm (calmer than Haddock in any case) when they spot the periscope from the submarine that wants to sink them, and retains a positive attitude, convinced that “all isn't lost yet”.
It also explains his rock-solid belief that Chang is alright in Tintin in Tibet: Chang, as Tintin’s friend, should also be invincible (and again, comic book logic proves him right), hence Tintin’s stubbornness throughout the album. We see Tintin repeatedly dismiss any signs that Chang couldn’t have made it because it doesn’t align with his belief. In fact, Tintin’s dream about Chang is a manifestation of his belief in Chang’s invincibility, and it acts as a justification of sorts to go look for him.
This very belief in his and his friends’ invincibility also explains Tintin’s reaction to injuries: he’s very dismissive of his own injuries, refusing to stay in the hospital longer than strictly necessary in both The Black Island and Destination Moon. We also don’t see him very concerned about the Thompsons when they’re in the hospital in The Calculus Affair.
Tintin’s reaction to death is also pretty casual; aside from the first few albums where he does genuinely think he’ll die (particularly in Cigars of the Pharaoh), he tends to stay calm in the face of death. This is in line with my earlier point that Tintin stays calm in the face of danger.
But more importantly, he tends to brush off near-death experiences when they involve his friend. When Haddock nearly gets shot in the head by some monkeys in Red Rackham’s Treasure, his reaction is to tell him to calm down and that “all’s well that end’s well”, while a rather shaken Haddock snaps at the Thompsons for nearly getting him killed. Tintin also dismisses Haddock’s fear of dying in Prisoners of the Sun. Of course, we know it’s because he has information that Haddock doesn’t but it remains a rather cruel attitude towards Haddock, and shows that Tintin sometimes forgets that not everyone is as sure of their invincibility as he is.
It’s during their trip to the moon, Tintin comes close to losing Haddock for the first time. He yells at him for it, but then immediately tells him to forget it once they’re safely back inside. Tintin, when confronted with a near-death experience like that, would rather ignore it rather than consider he might be wrong about his and his friends’ invincibility. He’s once again forced to face the possibility that Haddock might die when they’re back on earth, and we do see him worry for real that time. But since the album ends shortly after Haddock revives, we don’t see how Tintin reacts beyond the initial relief that he’s alright.
However, we see him dragging Haddock on increasingly dangerous adventures in the following albums. In fact, prior to the moon adventure, the only adventure where Tintin and Haddock are faced with adversaries that are trying to kill them is in The Seven Crystal Balls and Prisoners of the Sun (Land of Black Gold doesn’t really count on account of Haddock having joined Tintin of his own volition and therefore wasn't dragged into it). This suggests that, if anything, Haddock’s near death and miraculous recovery has further convinced Tintin that he’s invincible.
Tintin’s attitude to death only begins to change following Tintin in Tibet; outwardly, Tintin doesn’t dwell on the cliff scene more than strictly necessary, but nonetheless, this is the first time that Haddock’s life is endangered as a direct result of Tintin’s actions, specifically by his decision to ply Haddock with alcohol in an attempt to get him to change his mind about following Tharkey down the mountain. In the past, his life is primarily endangered by Haddock’s own actions or by the villains of the album, never by Tintin himself, and this obvious leaves Tintin a bit shaken.
As a result, we see Tintin become less impulsive in the following albums. In The Castafiore Emerald, they stay home and Tintin is shown being more concerned about Haddock’s well-being while he’s injured. In Flight 714, Tintin actively tries to avoid trouble by initially refusing Carreidas offer to get on his plane, despite having no proof that anything bad would happen, and in Tintin and the Picaros, he refuses to go to San Theodoros, even though his friends are in danger, and only goes after Haddock goes without him.
And while Tibet is not the last dangerous adventure Tintin and Haddock embark on, it is the last one that they go on of their own volition. This suggests that Tintin’s attitude towards his and his friends’ well-being has changed following the trip to the Himalayas. It’s especially noticeable when you contrast his attitude towards going to Khemed in Sharks and to San Theodoros in Picaros; one can argue that the situation was significantly more volatile in Khemed, but Tintin didn’t hesitate to go, while he outright refuses to get on a plane to San Theodoros despite the Thompsons and Bianca Castafiore being held prisoner there and, arguably, in more need of his help than the emir was. By that last album, Tintin is (rightfully, in my opinion) finally placing his and Haddock’s well-being and safety above others’, making him more cautious than he was in the earlier albums.
