The men are having an after work meal and drinking the typical beverage, Soju the popular drink here. From Wikipedia:
Soju is a distilled beverage native to Korea. Most brands of modern soju are made in South Korea. Though traditionally made from rice, most major brands supplement or even replace the rice with other starches such as potato, wheat, barley, sweet potato, or tapioca (called dangmil in Korean). Soju is clear in color and typically varies in alcohol content from about 20% to about 45% alcohol by volume (ABV), with 20% ABV being most common. Its taste is comparable to vodka, though often slightly sweeter due to the added sugar in the manufacturing process.
And it is cheap, I’m told about $1 per small bottle.