There isn't a single millimeter of space for me to squeeze into that back-and-forth unfolding right in front of me.
Literal
Eye [gen-の] front [at-で] unfold-[passive-られる] exchange [topic-は], I [subject-が] enter-into gap [emphatic-なんて] one-millimeter [even-も] doesn't-exist.
目の前 ('in front of one's eyes') plus で for location: 'right in front of me.' 繰り広げられる is the passive of 繰り広げる ('to unfold, to develop'), used attributively as a relative clause — 'the exchange being unfolded.' 入り込む ('to squeeze in, to enter into') is a compound verb. 隙 ('gap, opening, chance') is paired with なんて for dismissive emphasis. 一ミリもない is 'not even a single millimeter' — a vivid Japanese hyperbole using a specific unit. The overall sentence is long but richly descriptive.