Fun Fact: None of the actors but Gene Wilder knew that the tunnel scene was coming. Like, they had the lines and stuff, but they thought it was just a boat ride. And when the lights came on and he started singing their terror was real
This happened a lot throughout the movie. Which is one of the reasons it’s such a great film. The directors did the same thing when they all saw the inside of the Factory for the first time. They wanted to show the face of pure imagination. To capture it all.
Same thing with the scene where he comes out of the factory to greet them. None of them had gotten to meet Gene beforehand, so when he came out all hobbled on the cane and they had these confused looks on their faces and look actually concerned when he starts to tumble forward? That’s all legit. This whole movie was successful because it fucked with everyone who wasn’t Gene Wilder.
You guys know the sad Charlie reaction pic I use so much? That’s another ad lib scene. In rehearsals, gene was a lot calmer, but when they were actually filming he exploded on Peter ostrum (Charlie). That sad expression is genuine. And tht’s what it’s basically my favorite reaction picture ever.