으면 망하다

if X, you're finished

A conditional "-(으)면" plus 망하다, "go under, be ruined". It states a fatal condition: a company making three billion would have gone under, without the bailout it goes bust, if those two go head to head it's ruined, they said cutting it off would ruin them. It also does a lighter, jokier version of the same warning — eating the soup and bread first ruins it, absolutely not. The past 망했다 works as a flat "we're done for".