Some of these pictures and descriptions may give away plot details that you might not want to know before watching the film.
This is a movie about Irish troops fighting with mercenaries during a civil war in the Congo in the early 1960s. The troop are from the pitiful island of Ireland which sadly has no snakes, so when snakes show up, they get panic.
Early in the film we see some Irish soldiers digging trenches as a snake crawls towards the edge of the hole. A soldier named John Gorman (Ronan Raftery) looks up, sees the snake, and runs out of the hole, cursing and shouting "It's a f**king snake!" Then another soldier digging a different hole jumps out screaming "Snake!" The Commandant Pat Quinlan (Jamie Dorman) tells the men "These ones aren't poisonous. Did you not read the info packs?" Another soldier says "With all due respect, boss, are you sure they're not poisonous?" To prove himself to the men, Quinlan then jumps into the hole, grabs a snake with his bare hand, and throws it out of the hole, shouting "Get out!" Then he grabs a second snake and throws it out shouting "Out you f**kers!" Then the soldier who asked him if he's sure they're poisonous says "St. Patrick himself" referring to the saint who is credited with driving all the snakes out of Ireland. (I don't know why they celebrate him as a saint - he should have been locked up for the crime.)
This is another example of snakes used in a movie to give the hero something to conquer to prove his mettle, but I was glad to see he didn't see a need to kill them, like most movie heroes.
I don't understand why wild snakes would crawl into large holes like these did. After he threw the snakes, there's a shot of Quinlan staring at what I assumed was one of the enemy in the distance, and I though for a moment that maybe he released a bunch of snakes to scare the Irish. But that's just as absurd, since there's no way to control where those snakes would go, unless he put them in the holes himsel. It's not clear, also if we see any real snakes. They could be a combination of pros and CGI.