一不做，二不休

一不做，二不休:

Literally means:

once it is started, go through with it

Actually means:

be determined to go the whole hog

It means that once something is started, it will be carried through whatever the consequences.

It also means that, now that something is done, things resulting from it may as well be done. It implies aggravating the situation.

指事情要么不做，要做就做到底。

也指某件事情既然做了，由此引起的事情也索性一块儿做了。含有扩大事态的意味。