Wa-kāna ṭawā refers to an intention already concealed in the past.
Sa-aqḍī ... thumma attaqī projects an action, followed by a second planned step.
Matā yuẓlam yuʿāqib sets out a condition and its jussive result.
Mā jarrat ... wa-lā shārakat denies particular attributions of killing.
The grammatical contrasts map the story: concealed past → projected act → characteristic response → later accusations.