to top it all idiom UK (US and Australian English to top it all off)
C2 更糟的是
If you have been describing bad things that happened, and then say that to top it all something else happened, you mean that the final thing was even worse.
The washing machine flooded, my car broke down, then to top it all I locked myself out of the house. 洗衣机淹水了，我的车出故障了，然而更糟的是我把自己锁在屋外了。