Ether, this is a great senryu and I like the subtle rhyming, not sure if you did that intentionally or not though.
Title: links in nicely with the whole piece and I like it because on this site we may all enjoy reading and writing poetry but not one of us is the same and we all have our preferences, that is what I felt the piece was about.
Line 1: I ask myself where is this world you are talking about then the next lines answer my questions but yes, there is a world out there for us all and we have to go and find it for ourselves nobody can do it for us though they can help... a bit like following our own dreams etc.
Line 2: Like Mark the word 'Key' here seemed significant to me because I believe you are opening doors that you never would have before to go forth and enjoy life more (maybe I'm wrong) but I did pick up on a self-restrained, quiet but proud person here that's going out into the big, bad world trying to find themselves.
Line 3: All I can say here is keep writing your 'fickle poetry' because even though it varies (which I like) they are always a joy to read.
I honestly can't recall if I've ever commented on your work or not, but I'm an avid fan of your writing. I just don't get much opportunities to sit down and write a meaningful comment. Anyways, onto the comment.
Let me start off by saying I love the play on concept of the title, you wrote a senryu named "my nature" (haikus & senryu share the same format, differ in theme and it's just clever).
" There's a world inside;"
I instantaneously thought of a snow globe, not sure if that was the imagery you were attending. I know you were trying to expand from your title 'nature -> world', but just thought I'd mention it. Upon reading the entire poem, the imagery I got was a snow globe being opened and all these cut out word snippets from newspapers falling out. I've always found cut-up poetry intriguing in nature, particularly the aspect of it being aleatory. But I digress.
"I turned the key, and out poured"
I've mentioned how I visualized the whole senyru. Upon reading it a second time, I picked up on the significance of the key, it seems to be indicative of the speaker's reserved nature, which you strengthen with the last verse. I also like that you chose the word 'poured'; it seems more violent then as opposed to 'trickled', which might be one of the reasons why the speaker bottles up this 'world'.
I' already laid out most of my thoughts, but just wanted to say that I like the word choice 'fickle'. It paints the speaker as this 'troubled artistic type' (sorry, couldn't think of anything better than this cliche). It just shows another layer of depth to the speaker. Also, I've read your pieces and there is some variance between them, there is no central theme that your poems are cookie-cutter shaped from (that doesn't flow well off the tongue, but I"m hoping you understand what I meant).
I'm not too sure as to what else I can say, other then keep sharing these fickle poems. :)