He could feel the anger 'boiling up' inside him. [=he could feel himself becoming very angry]
The water in the pot is 'boiling over'. = The pot (of water) is 'boiling over'.
The kettle (of water) is 'boiling'. = The water in the kettle is 'boiling'.
(..) I bet I'm getting the cold one, I just know. I didn't-- I shouldn't even have to ask that question. I fancy a cold water tower, please. Because it's-- I've been boiling in this costume. I'm just a little bit disappointed. I did have a shower before I came to work this morning. WOMAN : (..)2012 The Hobbit: An Unexpected Journey