ear insufflation & modified stethoscopes question

I read on this forum that for ear insufflation you can simply put the tube into the ear, one can also use modified stethoscopes for both ears. the convenience of the modified stethoscopes is good, however I have some question, can someone done this help me?
MaCabe in his book said insert the tube into ear while tilt the head, let some pressure out to avoid pressure building in the ear, and the heavier ozone will fall down to avoid breathing ozone. My concern about the modified stethoscopes is that if it very fit into the ear just like a ear plug, then the ozone can not get out and the pressure build up, or it can be fit into ear loosely? and secondly, the escape ozone will at the same level as the nose and mouth, then may breath in. Is it a concern or the quantity is small and need not to be worried?

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