Terrain may Kill, but its primary function is to detox and to stimulate detox pathways. It is through the stimulating of the detox pathways that the "junk" gets removed. Any killing that happens is due to this pathogen being a major contributor to this pathway not functioning well.
No other detox needs to be run. If the Terrain causes too much grief, then Pause it to allow the body to catch up, then continue. Some people need more time to get through it, but that is OK. We all have to progress at a rate we are able.
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