I read this in Word by Word by Kory Stamper:
It will be 3 p.m. on a Wednesday in April; you will glimpse preternaturally sunny weather through the silver of window near your desk; the shouts of children walking home from school will sound both alien and familiar; cool, metallic panic will slide down your gullet and wave up at you from your stomach.
I couldn't find any definition of "metallic" fitting into this context. I also don't understand what "wave up" and "silver of window" means here. Could anyone help me out?