How does lochinvar's dance with the bride affect the outcome of the poem "lochinvar"?

In the poem “Lochinvar” by Sir Walter Scott the dance and the wedding day is crucial for the outcome of the poem. On the day of Ellen’s wedding Lochinvar asks her for the dance and while they are dancing he proposes to her to run away with him and she accepts: “One touch to her hand, and one word in her ear,/When they reach’d the hall-door, and the charger stood near; /So light to the croupe the fair lady he swung, /So light to the saddle before her he sprung!” 

answer: how the techniques the author's use accomplish their purposes

happy birthday to you
happy birthday to you
happy birthday dear (name)
happy birthday to you.

from good friends and true,
from old friends and new,
may good luck go with you,
and happiness too.

alternative ending:
how old are you?
how old are you?
how old, how old
how old are you?