Possible Clues:

• Occur as a result
• Come about the happening before you had a meal
• Turn up day before new gallery closes in university
• Does it turn out that this was the happenig you took as a matter of a course? (9)
• This could turn out to be the happening you swallowed
• It's not so odd to start the happening you swallowed, by the sound of it
• The happening you swallowed may thus come to pass
• Turn out still tight, done over by end of binge
• This might happen as a result of something you ate
• This turn out may happen over what you swallowed