if the balloon goes up, a situation suddenly becomes very serious or unpleasant.

The balloon went up last Friday when the scandal became public.

• be in the firing line
• be in the first flush of
• be in the first flush of something
• be in the frame
• be in the front line
• be in the grip of
• be in the grip of something
• be in the groove
• be in the hole
• be in the know
• be in the land of nod
• be in the land of the living
• be in the lap of the gods
• be in the limelight
• be in the loop
• be ... in the making
• be in the market for
• be in the market for something
• be in the money
• be in the nature of the beast
• be in the picture
• be in the pink
• be in the pipeline
• be in the public eye
• be in the pudding club