Well, don't let NPCs fall to their death if they are potential companions.
These problems arise when a game engine starts as a generic physics simulation and various restrictions/rules mandated by gameplay design are added as an afterthought.
This may sound a bit silly, but depending on the story needs, these can potentially be completely separate entities. That way you wouldn't need to create a weird crossover entity that switches between friendly and enemy AI components etc.
These problems arise when a game engine starts as a generic physics simulation and various restrictions/rules mandated by gameplay design are added as an afterthought.