Since most animals pass through a moment early in life called gastrulation, in which an embryo, consisting of a hollow ball of cells, indents to form a cup, the "inside" of the animal isn't really the inside of the cup, it's between the deflated walls of the former ball.
Further, since the cup closes further and forms a small hole, and a mouth later develops on the opposite side, the "inside" of the animal isn't the digestive tract but the body cavity that exists between the external surface and the plumbing of the tract.
Therefore, the inside of our mouths, the inside of our stomachs, our intestines, and our colons are really the "outside." Same thing with our lungs. And if we look even closer, the micropores that allow nutrients to pass from our GI tract and oxygen to pass to our bloodstream, are open windows to the "outside," and the distinction between what's inside of us and what's outside of us gets very blurry, and if we look close enough, we can no longer draw a line between ourselves and the external world.
In that case, are we really "we"?