《俺が威嚇射撃する ゴーを出したら 突入だ》
I will fire a warning shot, when GO begins (must) rush in.
My shot at figuring out a translation above.
I figure it's something like, I will fire the warning shot, then say go, then we proceed, which is what happens next in the show. Just now seeing how it all connects grammatically.
《瀬文隊長が威嚇射撃後 ゴーの合図で突入します》is spoken right before they go in by another officer. From that it's clear that:
After the commanding officer fires some warning shots, on the signal "go", we storm in.