Joaquín "El Chapo" Guzmán's movie-style escape through a tunnel from his cell in a maximum-security prison in July last year shone a global spotlight on how vulnerable Mexican jails can be to corruption.

The recent flight of two convicted kidnappers — who walked to freedom after sawing through some metal bars while they were supposed to be in the bathroom — has highlighted the fact that Mexican jailbreaks are not just the privilege of world-famous drug lords.

According to government statistics, 590 prisoners escaped between 2010 and 2015 — an average of about two per week.

A closer look at the figures shows that mass escapes from prisons in drug wars zones peaked in 2010 and that the number of escapees has fallen since then. Even so, there remains a steady trickle of jailbreaks involving less people but still underlining how corroded Mexican prisons are.

"The government's response has been to try to minimize what happens, try to make it smaller than it is in order not to reveal the underlying problems," said Leslie Solís of the policy watchdog México Evalúa. "If the government doesn't do anything it will keep happening."

Roberto Sánchez Ramírez escaped from prison for the first time in 1991, reportedly dressed as a woman. He also escaped in 1998 and 1999, earning himself the nickname El Fugas, or The Escaper.

Sánchez's fourth escape took place last Monday from one of the four major prisons in the Mexican capital. He was accompanied by fellow inmate Agustín Miranda Orozco. Together their sentences for kidnapping and other violent crimes reportedly add up to 178 years.

Sánchez and Orozco were suddenly called from the prison to a hearing in an adjoining courthouse that is reached through a tunnel. Once in the waiting room of the courthouse, both inmates asked permission to go to the bathroom from the two guards who were supposed to be watching them.

The guards then waited outside the restroom for the next 15 minutes, but the kidnappers were not actually there. Instead they were breaking into a storage room by severing some thick metal bars and smashing a hole through a dry wall with the help of tools that just happened to be there.

Embarrassed officials later told reporters that the prisoners then disguised their uniform with clothes that were in the storeroom, and walked out of the courthouse through the main door. They then crossed a car park and left the facility, disappearing into the 25-million strong megacity beyond.

"Obviously there was a total lack of care and of commitment on the part of the guards," Hazael Ruiz, the head of prisons in Mexico City's government told reporters. "The prisoners have the right to go the the bathroom, but there were a series of protocols the guards didn't follow."

Many are also questioning why two judges suddenly ordered the two prisoners to go to a hearing. How, many ask, did tools and clothes appear in such convenient locations, and how could nobody notice the inmates walking out of the gate.

The chronic corruption and endemic ungovernability in Mexican jails is not just seen in the number of escapes. It is also evident in the dozens, sometimes hundreds, killed behind bars each year.

This week also provided a stinging example of that violence when three inmates were killed and 14 injured on Wednesday night in the Topo Chico prison in northern Mexico. The murders took place just three months after a night of terror left 49 people dead in the same jail, including four who were not registered as being either prisoners or guards.

"I'm not surprised by what happened in Topo Chico or what happened with El Chapo," said Maria Elena Morera of the anti-crime group Causa en Común, or Common Cause, to emphasize how little real control the authorities in Mexico have over the country's prisons.

"What I'm surprised about is that there are not hundreds of riots and thousands of escapes."