The final battle made no sense

Poles ride left to right on screen.
Cossacks ride right to left.
Cossack reinforcements join in the middle.

And then we're treated to a tight posse of riders riding towards the cliffs.
They approach, slow down....
Then in close-up it's somehow the Cossacks pushing the Poles over the edge?

How on earth did the battle get that fluid that the whole thing could relocate itself a mile further down the Steppes?

When all of your wishes are granted....
Many of your dreams...will be destroyed