What is it in canned biscuits that makes them puff up immediately upon opening the can yet stops them from raising further? What kind of food voodoo is at work here? Please explain the food science behind this and what additives cause this effect in the "food". 
I used to make the store brand version of the Pillsbury canned biscuits.  It was true that the CO2 is the gas that creates the pressure.  The dough is made by measuring all of the "scaled" ingredients to get the proper mixture, which in turn controls the amount of gas created.  It is then pumped onto a conveyor where it is sheeted.  This is similar to rolling it with a rolling pin.  This is how the thickness is determined.  After that it is cut with a die similar to a cookie cutter.  (although for mass production and varies based on what size and shape desired...Look up rotary die cutting for biscuits-- this was not the tool we used but is the most common way that bakery manufacturing cuts sheeted dough).    We did retard the gassing by keeping the production room cool until the product got to the canning process.  Then we allowed the process to warm.  This allowed the cans to "gas up"  This process actually helps the can seat or seal.  The metal lids are just crimped (rolled with cams) onto the cardboard side.  The gas actual pushes on the can structure until it latches together.   