Perhaps you mis-read my post.
PJ take her in. PJ go for lunch. PJ conveniently leave an adjoining door open. PJ come back. PJ find Leonor getting filled in by inmates. PJ state 'she threw herself down the stairs' so inmates don't get the blame and there's no evidence on PJ.
You can happily rearrange the sequence with the PJ filling her in if you like. My point is either are possible given the atmosphere that must have been prevailing when word got round that she is in the building.
Shall I set the scene for you?
It was approaching the witching hour one late October night in Faro police station. Goncalo Amaral was sereenly awaiting for news from his officers regarding an appropriately-sized freezer at the Cipriano residence. There were no escapees secretly raiding the vast drinks' cabinets.
Leonor had been brought back to the station 4 hours after having been returned to Odemira prison. Her (alleged) previous confession to PJ officers, admitting to killing Joana by dubious methods, left a lot to be desired. PJ needed to speak with her again "lest Joana still be alive" (somewhere in a pig pen).
Leonor was interrogated by Cristovao*, a PJ Inspector well-versed in child trafficking & various forms of thuggery.
She needed a bathroom break & was accompanied by 2 other PJ officers to the restroom.....
*Cristovao sentenced twice in the last decade for various forms of corruption, kidnapping, armed robbery etc for 4.5 & 7.5 years yet remains a free man.
None of the people who tortured Leonor could be identified due to falsification of reports. Meanwhile, the victim had additional time added to her custodial sentence. I'm don't think that anyone should ever accept the court judgement was a delivery of justice.
*Edited to correct name of police station