Bursting through

[Vespasian28]

Had a situation today that we could not agree on so diced for it.

A unit of LH evades a charge directly to it's rear where it meests a friendly mounted cavalry BG at roughly right angles to it as it is facing enemy LH to it's own front.

The evading LH obviously cannot interpenetrate so they shift sideways but cannot complete the evade move as it then runs into the enemy.
So, our reading of it is that as it cannot complete the evade, no shift is allowed and it must instead burst through the friendly cavalry.
However, it can only complete the burst through if there is room beyond for it; which in this case there is not as there is no room due to the enemy.

Consequently the evaders are destroyed.

So far this is our interpretation and we agree up to this point.

However, I think the enemy cavalry were being burst through and therefore drop a cohesion even though the burst through could not be completed.
My opponent thinks that as there was no room beyond, the evaders burst through would not have happened and therefore no drop.

I lost the die roll.