This is actually going out of denial, and really just seeing ourselves just the way we are. Agreed, we have a pretty fucked up side of us, but also a true potential for love and sharing.
These 2 sides are mixed, in conflict, and ever-evolving, but really, they are us. It may appear terrifying, but really, when you see it, it has a freeing and peaceful quality to it, because you just "know" that this is true.
It mostly shows things that usually stay in the unconscious part of our mind. It is more like a lens than a seed.
Of course Barely being able to contain violence is concerning, but let's face it, it is a daily struggle for a LOT of humans. Our good intentions dp not always weigh up when for example we are starving to death. Anger, greed or hatred, are some of our common struggles, but most of the time they stay hidden in our subconscious, bc we do not like to see ourselves as persons able to perpetrate violence.
But only when we see it (it requires honesty, not necessarily lsd xD) and we resolve to work on it, can we really grow.
I didn't interpret the post as "I was feeling barely containable violence then" but more of a "I became aware of the barely contained violence that me/humans have under the surface". As in, a change of judgement on his current and past condition, rather than a new emotion.