What is the meaning of "in the second that the hammer hits" in Elton John's song "The One"?

English is not my first language and I am not sure what the meaning of "in the second that the hammer hits" is, in the lyrics of Elton John's song "The one". I know the meaning is not literal (i.e. a hammer hitting) but rather an idiomatic expression. Just not sure what the idiomatic meaning is. Could anybody please explain or even better re-phrase this part of the lyrics for me? I like the song very much and am just trying to understand all the lyrics. Thank you so much.