I'm with Jason on this one.
Boiled peas won't grow - evidence that they have been killed by the boiling process. The high temperature irreversibly destroys crucial proteins in the plant cells, including structural proteins, so the cells fall apart (that's why the water goes green when you boil them) and cease respiration.
That said, your boiled peas might quickly become colonised by bacteria and fungi which will move in to consume the readily available sugars released by the boiling process. These opportunists will definitely be respiring, and could account for apparent oxygen consumption by previously boiled peas !
"I never forget a face, but in your case I'll make an exception"
- Groucho Marx