In a brazen and meticulously planned escape, 17 undertrial prisoners broke out of the Thekkampatti sub-jail here late Monday night after staging a fake medical emergency and overpowering prison guards, but luck ran out for 13 of them as a relentless police crackdown ensured they were back behind bars within hours.The dramatic jailbreak unfolded at around 10 pm on Monday. According to prison officials, the inmates triggered panic inside the cell by faking a severe medical emergency, claiming one of them was suffering a violent seizure.Responding to the cries for help, unsuspecting warders opened the cell door to render assistance, only to be violently ambushed and overpowered by 17 prisoners in the block. The inmates snatched the keys and opened the main entrance and escaped.Director General of Prisons Sandeep Rai Rathore, who rushed to the spot to inspect the sub-jail and oversee operations, confirmed that 13 of the escaped prisoners have already been nabbed following a coordinated, high-intensity search operation.