Implementing Presentation-Abstraction-Control architecture with Mediator design pattern installed on the Control

I'm working on a tower defense (TD) based game with Unity 4.6.1 engine using C# plus .NET framework. Obviously, TD is an interaction oriented application (towers - towers, mobs - mobs, towers - mobs) so i have decided to use hierarchical PAC architecture approach.

A common implementation of PAC is that Strategy installed on Presentation and Mediator installed on Control as far as i know and it makes me confused. I have installed Observer design pattern for about 100 times but 0 times with Mediator. Although the concept of both pattern are 80% the same i still cannot figure out how to properly install Mediator on the Control of PAC.

So can anyone show me how to properly do this using C# with .NET framework and Unity engine?

An example case study is great but any experience will be appreciated!