How to effectively push your friend off of Taal's Horn Keep

As demonstrated below the area in red cannot be passed without a players input, therefore rendering our efforts useless for pushing our (preferably AFK) target off the map.

In order to get over the "edge" you have to direct your efforts towards the books on the ground (image below for demonstration).

What you are trying to achieve here is to continue pushing until their player model is actually pushed on top of the books, this will create a state of limbo allowing you to gain the advantage and actually overcome the "edge" entirely, something of a glitch if you will.
As shown above the player is hovering, once this is replicated we can move on to the final step of overcoming the "edge".

What you want to do at this part of the segment is to push the player model off of the books in the direction of the cliff until they actually drop off the books (image below for demonstration).

Amazing! we have surpassed the "edge" and can continue to push our adversary, freely mind you, towards the cliff and complete our objective.

Once the player has been pushed off the cliff, you can promptly wait for them to respawn and continue this until either they return or you are put in a game.

Honestly i find it tedious that Warhammer: Vermintide 2 hasn't fixed this issue entirely. This guide wouldn't have to exist if we where able to simply push our teammates effectively outside of the Bridge of Shadows within Taal's Horn Keep.