nairobi dramatic picture kenyan opposition lawmaker caleb amisi luyai lean window car tear gas billow police fire convoy opposition politicians nairobi oct. 13. police act prevent politicians enter center capital enforce ban stag political protest ahead repeat presidential election kenya hold re-vote oct. 26 supreme court throw result election august incumbent president uhuru kenyatta opponent raila odinga boycott repeat argue hold wide-ranging reform adopt prevent another fail vote reuters photographer baz ratner take image main challenge cover story protest move fast different focal point around nairobi ratner ride ahead opposition convoy motorcycle tear gas canisters fire stop side road put gas mask notice one cars engulf smoke move forward slowly run towards take photos ratner recognize driver luyai opposition member parliament saw lean window gesture help open door walk side people car lie floor quickly car drive away ratner say picture story tear gas nairobi