You observe a patient wearing anonrebreathing mask and note the bag completely deflates with each inspiration

A non-rebreathing mask if deflates then there will be no air for breathing of the patient.

Explanation:

In medical treatment, Non-rebreathing mask is used as a source of oxygen delivery to the patient without any medical assistance. It has a reservoir bag in it which is connected with an external oxygen cylinder which supplies oxygen.

The inflated bag gradually deflates every time the patient respires. However, if the bag completely deflates then there will be no source of oxygen for the patient resulting in complications. It should always be replaced once it gradually deflates.

when you rub, you also apply pressure, that pressure can urge the poop to come out. i think that when your rubbing, you also might be slightly breaking it up and that can further fill the stomach.  

answer; monaxial;