Mexican drug kingpin Joaquin “El Chapo” Guzman stuffed himself down this narrow hole chiseled into the concrete floor of his prison shower when he broke out of Mexican prison, the latest pictures from the breakout show.

The 20-by-20-inch hole led to a sophisticated tunnel away from Altiplano maximum-security prison in Almoloya, Mexico, to a half-built hut about a mile away.

The filthy bathroom provided the perfect place to build an escape hatch because the prison’s security cameras were pointed away from the shower and toilet out of human rights concerns, providing a blind spot where Guzman could disappear undetected.

Mexican authorities say the intricate breakout scheme must have involved considerable outside help and planning that started even before he was thrown in prison. His escape included riding on a red motorcycle through the tunnel, which was complete with lights and ventilation.

Investigators found a sparrow in Guzman’s prison cell trash that they believe his accomplices used to test whether the air in the tunnel was safe to breathe.