Tensions ran high in the Philippine Senate following a leadership ouster and the appearance of a fugitive ex-police chief. The situation dramatically escalated into a terrifying shoot-out within the building.

Tensions were already high on Wednesday night in the Philippine Senate, days after lawmakers abruptly ousted its leader and an ex-police chief wanted by the International Criminal Court showed up after six months in hiding. But few could guess at how suddenly terrifying things were going to get. Hours after wanted Senator Ronald dela Rosa had serenaded a group of reporters with the alma mater song of the Philippine Military Academy and declared his right to sanctuary from arrest in the building,...