The structure 还没…就… is used to indicate that either an action or an event happened or is happening out of order.
还没 is followed by an action that will happen later, and 就 is followed by an action that happened before.
Scheme
subject 1
还没
predicate 1
subject 2
就
predicate 2
Examples
你还没告诉我就先对我妻子讲了,为此我非常生气
You haven’t told me about this yet, but you have already told my wife. I am so angry!
nǐ hái méi gàosu wǒ jiù xiān duì wǒ qīzi jiǎng le, wèi cǐ wǒ fēicháng shēngqì
我还没来得及解释,他就挂了
Before I could explain it, he hung up the phone
wǒ hái méi láidejí jiěshì tā jiù guà le
度假回来还没过5分钟,就感觉好像我从未离开过
Not even five minutes have passed since I returned from vacation, , and it feels like I’d never left