The problem with critiquing poetry if that grammar rules can be bent or broken in pursuit of aesthetics. "whenever you go" sounds somewhat odd here. "whereever" might be better. "whenever" can be used, however. "lighter" can work here, but I think it would be taken to mean having a lighter heart in a dangerous situation, rather than brightening a metaphorically dark place. "and nothing contaminates" is jarring. "...with nothing contaminating its shining purity or impeding..." is better. Or "and let nothing contaminate...or impede..." "torrent" can be used there, but it sounds odd to me.
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