Watching this scene as a kid, it was merely a goofy and funny moment.
Now as an adult, it is a legitimately touching and emotional scene even with the humorous hyperbole. This is a scene of two friends who decide to bank it all on a gamble, a one way trip into the unknown and where Harry decides to put his own desire on hold so he can help his friend fulfill his own. As silly as the movie is, it is actually a great portrayal of two true friends in a world where such people are a rarity.
The part where Lloyd gets serious at 4:00 feels like a dramatic scene from a completely different movie. Carrey showed how he was capable of doing drama as good as comedy, even better maybe. And he won 2 Golden Globes for his dramatic performances like 4 years later.