Well, it wasn't light yet when the gunfire starts.
( Well ( , ( it ( ( ( ( was n't ) light ) ( yet ( when ( ( the gunfire ) starts ) ) ) ) . ) ) ) )
(ROOT (S (INTJ (UH Well)) (, ,) (NP (PRP it)) (VP (VBD was) (RB n't) (ADJP (JJ light)) (SBAR (ADVP (RB yet)) (WHADVP (WRB when)) (S (NP (DT the) (NN gunfire)) (VP (VBZ starts))))) (. .)))
When the gunfire starts, it was not even light yet.
( ( When ( ( the gunfire ) starts ) ) ( , ( it ( ( ( was not ) ( even ( light yet ) ) ) . ) ) ) )
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (DT the) (NN gunfire)) (VP (VBZ starts)))) (, ,) (NP (PRP it)) (VP (VBD was) (RB not) (ADJP (RB even) (JJ light) (RB yet))) (. .)))