The Eighth House is usually kinda scary for most people. The reason the Eighth House has this reputation is that it oversees sex, death, and anything else that needs to transform. The part of the body that this house oversees are any organs of elimination. For the sake of brevity, we will limit them down to "the bladder".
The kidneys filter, the bladder holds until elimination can occur. Hence, transformation of something in the body shows up outside the body, and we all know how that happens. Likewise, reproduction is governed in part by fluids and their movement, and we should have an understanding of how that happens. (If you do not, then go ask your Mom or Dad. If you cannot do that, then we are out of luck here)
Likewise, when a birth or death is occurring something is either entering or leaving the world and is transferring either into or out of a body.
Scorpio is the sign that traditionally rules the Eighth. This House has a way of breaking down our barriers so that where we start and where someone else starts can be harder to understand. In any of the above-named events, the distinction between inside and outside is simply a matter of time. So, it is not the case that it is purely internal, and it is not the case that it is purely external but it turns out that it is both.
Maybe we will develop some understanding about this when we go on to the Ninth House.