What is the understatement in poem cremation of sam mcgee?

In the famous poem "The Cremation of Sam McGee" by Robert W. Service, the speaker mentions how he and Sam McGee left "some whiskey there for drinkin', but none the less for sewin' in." This line suggests that they left an excessive amount of whiskey behind. On the surface, this may come across as a casual remark about their whiskey consumption. However, considering their extreme circumstances and the perilous environment they were in, the fact that they left behind such a significant quantity of whiskey underscores the intensity and despair of their situation. This serves as an example of understatement, where the speaker's words convey more than just the literal meaning and subtly allude to the dire nature of their journey and the grim reality they faced.