What is the plot of "Out, Out --" by Robert Frost?"Out, out --" poem by Robert Frost

The poem "Out, out --" by Robert Frost is titled as an
allusion to a passage from Macbeth by Shakespeare.  In the allusion
passage, Macbeth is commenting on the fragility of life, and the meaningless of death. 
The dramatic situation of this poem is about a teenage boy who is "doing a man's work"
on the family farm.  He is just about done for the day when the chainsaw in his hands
"leaps" from his control and cuts off his hand.  He is in such shock as what has
happened that his first instinct is to laugh, but then the speaker tells us the that
"the boy saw all."  This suggests that he sees all of the reality of the situation:  he
has lost his hand; he sees that he is losing a lot of blood; he sees that he is in deep
trouble.  Once the doctor arrives, he puts the boy under the anesthetic, ether. Then,
shockingly, the boy dies!  As they are checking his pulse and breathing, they see his
life just quickly fade away.  The death of the boy who died too young is a clear
connection to the Macbeth speech -- his life was blown out like "a
brief candle." (Which is the line of the allusion.)  While the death of the boy is
troubling, what is more disconcerting is the last two lines of the poem.  The speaker
relates to us that "there was nothing more to build on there."  It sounds rather
dismissive of the boys life and his death.  This attitude is compounded in the last line
where we learn that those around the boy, went "back to their affairs."  This could mean
that they did what they had to do to deal with the dead body, but it sounds more like
they just walked away because there was nothing more to do and went back to whatever it
was they were doing just before the accident.  If that is the case, it is a further
connection to the Macbeth speech where Macbeth says that life is "a
tale, told by a fool, full of sound and fury, signifying nothing."  Could that be true
for the young man?  Is his too short life, his foolish/accidental death, and the
aftermath just meaningless in the bigger picture?  Frost certainly leaves his readers
with something to think about here.