Imagining Disaster, previously "Stuck," edit 1

[Shay]

Hi there, about to return the favour  
A lot of points have been made already, so I'll comment as best as I can without being too repetitive. 

Pen a centimeter from the page, - this would read more smoothly if "centimeter" could be replaced, perhaps by "inch/lenght". 
       poised—
       like a statue:
       Could I stick this way?

Could sticky sap encase me,
swamping my throat, swallowing - beautiful segment, very vivid descriptions of an intriguing thought process. 
my words, muzzling my mouth?
I'd be stopped in a lollipop,
       with my pen
       as the stick!

Could salty tears seal me,
—a corroded Tin Man— I really like the variation in the description here, smooth transition as well. 
my surface quiescent,
       permanently
       paused? - your usage of alliterations as a continuous stylistic device is done very well as it seems to be natural. 

Maybe I'd stick like Zen legends, - the preceding segments have been slightly abstract and I'm intrigued by the reference on hand. 
mummifying through meditation,
becoming a picture—
       a pose—
       in rigid repose. - my favourite segment so far. Regardless of the reoccurrence of "pose" here, the highly reflective picture you're painting with the "rigid" usage is very direct yet relatable as it carries an echoing thought of layers. The "mummifying/repose" is underlining this very feeling.

Maybe the rust slithering up my skin
is not a fetter but rather - personally, the word "fetter" doesn't seem to be as natural in this segment as the the overall composition might suggest. "tie/chain" could be possible options, but that's pure preference. 
a rattlesnake's rigor as I writhe - I'm not too sure about "rigor", it's a very nice continuation of the alliteration, nevertheless. 
up in coils and ready my venom,
       poising myself
       to strike. - a great reflective sentiment, I thoroughly love the directness displayed here, particularly in the "poising myself" bit. My only critique at this point would be that it somehow "ends" abruptly, as in I'd like to see a final scenery. 

This was a very enjoyable read. Great work, and thanks for sharing.