。
She broke down in tears when she heard about the accident.
Literal
She [topic-は] accident [possessive-の] thing [object-を] hearing, crying-collapsed.
泣き崩れる is one of those vivid Japanese compound verbs that English needs a whole phrase for: 泣き- (stem of 泣く 'cry') + 崩れる ('collapse, crumble') = 'collapse into tears, break down crying.' The image is physical: weeping so hard one's posture gives way. Compare with simpler 泣き出す ('burst into tears,' begin to cry) — 崩れる focuses on the collapse, while 出す focuses on the onset. 事故の事 ('matter of the accident, the news/details about it') — 事 in this slot just means 'about it,' a softer general topic frame.