The two prisoners who escaped from prison 27 in Sierra Chica had been placed in a pavilion of that prison that has an open regime. That is, with minimal security measures even if they had been convicted of serious crimes.
The passage through these units without severe restrictions in the controls is the step prior to obtaining freedom, conditional or definitive. The prisoners left in a Toyota Hilux van, because they had no resistance. The police were immediately notified and began a lockdown operation to recapture the convicts.