Perhaps a rule change for the Go-Away scream is in order. I would suggest something like this:
1. All pushes are executed.
2. Any Human to Zombie promotions are executed.
3. Any effects resulting in piece destruction are executed (engulfment, zombies on ichor or multiple occupancy squares, etc.).
4. Any petrifications are executed.
All partial moves under a single number would be deemed simultaneous.
Under this proposed rule, the owner of the Go-Away is unable to specify the order of effects. This will reduce the tactical complexity of these moves and hopefully render the programming problem tractable.
Whether it would overly damage the peculiar and interesting flavor of Nemoroth is a question I'm not qualified to answer.