The Russians have to withdraw now from the salient west of Kyiv or face a serious possibility of losing their entire forces here to encirclement.
On the map, the road from Ivankiv to Demydiv is where the stalled convoy was. Through Ivankiv is the only way out for the Russians now.
At Ivankiv is a bridge over the Teteriv river which is crucial to Russian forces' escape.
Russia tried in the last few days to attack Ukrainian forces at Teterivske and open another escape route but failed.