What are your thoughts concerning baptism when a finger or knuckle or possibly someone with long hair doesn't all get under at the same time or under at all? It seems like that could happen accidentally with no knowledge of it or could also be noticed by the baptizer. It seems like it's still an immersion. Just my thoughts.
The word baptism means immersed and it represents the burial of Jesus as well as the burial of a person's old life of sin (Romans 6:3-7). Most of us try to make sure a person is completely immersed and will redo a baptism if it is noticed that a person did not go completely under. Personally, I would not get upset if everything did not go under water at precisely the same time. It would still be an immersion.