Certainly you can see what Jerry does as an inititation rite. I say this because it has one very important thing in common with initiation rites in many cultures. What that is is the fact that it requires moral and physical bravery.
In many cultures, masculinity is associated with physical and moral/mental bravery. Men are expected to be tough-minded and as well as physically tough. To prove that they really are men, they are often required to go through some rite that forces them to prove they have these qualities.
Jerry has to prove he is tough-minded enough to try to swim the tunnel and that he is physically tough enough to manage it. This sounds much like an initiation rite.