Role Description: Architect 
You may make the following assumptions:

The case is in mediation.
The state of Colorado spent $850,000 to correct surface drainage problems around the facility and to repair interior walls and floors damages by swelling soils.
The contractor has already made a settlement with the state of Colorado.  No details of that settlement are known.

Your role is to protect the interests of your company.  You are concerned both about the cost of a settlement and the reputation of your company.  You realize there may have been some shortcomings in your design, but you feel most of the blame lies with the contractor.  Youre frustrated that the terms of the settlement the contractor made with the State are not being made available; specifically, you are not sure if the State has already recovered their costs from the contractor and now they are coming after you for more money). 
You never really have understood geotechnical engineers; their guidance and recommendations are confusing.  You have an incentive to settle the disputed during mediation.  You want to avoid a court battle which will cost you more in legal fees, take a long time, and perhaps tarnish the reputation of your firm further.  Youll go for a settlement you find fair, but you wont take all the blame. However, your goal is to maintain your firms reputation and kept the amount of the settlement as low as possible. 
Preparation
In order to prepare for the negotiation, prepare a list of facts both for and against each of the three parties in the mediation.

Owner
Architect
Geotechnical Engineer