Andy’s exemplary escape at the end of The Shawshank Redemption has been referenced time and again as an iconic moment in cinematic history. Based on the 1982 Stephen King novel named Rita Hayworth and The Shawshank Redemption, Frank Darabont's film adaptation chronicles a journey towards hope through perseverance, as undergone by the protagonist, Andy Dufrense (Tim Robbins). However, over time, a possible plot hole emerged: how was Andy able to dig a ten-feet long tunnel without anybody at the prison ever hearing him do so?
In order to understand and analyze how and why this was possible, one needs to look into the circumstances surrounding Andy, and the way in which he positions himself in the public eye at Shawshank State Penitentiary. Over the first two years of his sentence at Shawshank, Andy faced the brunt of harassment by the Sisters and remained isolated from his fellow inmates. However, over time, Andy was able to befriend those around him and even form endearing friendships with the prison guards. Moreover, he goes on to help the warden with his corrupt money laundering schemes with his knowledge of finances and tax law.
As a result, Andy was exempt from manual labor and protected from harassment to the point that Captain Hadley beat up the leader of the Sister, Bogs, after a brutal assault post which Andy ended up in the infirmary for a month. Never exhibiting signs of wanting to escape prison, Andy was unanimously viewed as a model prisoner, especially after he takes on a position to help out in the library, which he helps refurbish over a period of six years. Resultantly, Brooks Hatleb Memorial Library emerged as the finest prison library in all of New England, which understandably worked in favor of Andy’s reputation at Shawshank. A combination of these reasons explains why the Warden did not take down the Raquel Welch poster in Andy’s cell, which essentially covered the entrance to the tunnel.
Due to these circumstances, it is probable that it was easier for Andy to escape in Shawshank Redemption without anyone knowing about it, which is also why no one heard him digging the tunnel in the first place. Moreover, it is important to note that despite Andy’s cautious perseverance in escaping Shawshank, he built the tunnel over a period of many years - a testimony of his strong and unwavering resolve to experience true freedom. Apart from the dual factors of patience and time, Andy uses a little rock hammer to slowly chisel away the hole, which, when done quietly and carefully, is unlikely to produce much noise. The dust that was a result of the chiseling was periodically scattered by Andy in the yard, which is the reason why there was no tangible evidence of the fact that he was digging a hole, let alone a ten-foot tunnel.
While this is merely speculation, it is also possible that some of his fellow inmates were aware of Andy’s escape plan to a certain extent, but chose to ignore it, as it seemed like a long-shot in such a high-security prison. However, even if no one heard andy dig the tunnel, it is unlikely that not one person ever saw him do so, as he would have to climb inside the hole in order to dig out the rest of the tunnel at some point. Hence, it is unlikely that guards on nighttime duty were oblivious to the fact that an inmate appeared to be missing in their cell. Nevertheless, one needs to consider that cinema evokes awe and immersion due to a certain level of suspension of disbelief, and the narrative of The Shawshank Redemption remains timeless and impactful despite possible plot contrivances.