Other mistake: In order for Rastapopoulos to break into the secret passageway, he places chunks of dynamite around the idol, then lights a fuse for each individual chunk of dynamite, all burning at the same time. The fuse for the dynamite near the middle of the idol is significantly shorter than the fuses for the others. Despite this, it still takes the exact same amount of time for all three to burn down. (00:34:00)
Continuity mistake: When Allan realises that Rastapopoulos wants Carreidas alive, there is a grenade pin in one of his fingers from the grenade that he just took out. Allan then throws the grenade away, and the pin for the grenade has suddenly vanished. (00:28:55)
Continuity mistake: At the start, keep an eye on the tape strips over Carreidas' mouth. There is a vertical piece of tape directly over Carreidas' mouth, followed by another piece of tape from the top of his right cheek down to the bottom of his left cheek positioned at a sideways angle, followed by another piece of tape from the top of his left cheek down to the bottom of his right cheek also at a sideways angle. All three strips of tape are meeting with each other at a midway point by his mouth. However, when Haddock says "Come on" to Carreidas and Krollspell when they are under fire later on, the tape strips positioned sideways now meet each other at around Carreidas' left cheek area, further away from his mouth. (00:25:45 - 00:26:40)
Chosen answer: If Hector was seriously intent on removing King Ottokar's scepter from the glass cage holding it and launching it through the window with the camera, then Hector would have been forced to knock out the two guards so they would not have interfered with Hector's plan as soon as he removed the scepter from the glass. As for Hector, himself, was explained when Tintin was explaining how Hector stole the scepter. Tintin placed a twig inside the camera and it launched out of the camera. Hector would have placed the scepter inside of the camera, and would have been knocked unconscious due to the spring effect created when the scepter had been launched.
Casual Person