Exchange 2010 - 2 DAG members in 1 site / Witness Server and 1 node failure

Hi,

I have a 2 DAG members in only 1 site using Exchange 2010.

I know that if Witness Server and 1 node fail in a 2 DAG members configuration (for example because of a power outage) the cluster solution will fail.

So in that case, is there any workaround?

Is possible in that moment, just with 1 node running, to set another server as the Witness Server?
I tried it but as cluster service is down do not allow me to configure it.

I read about site switchover, but that is for different sites situation, I have only 1 site.

Thanks

Cristian L Ruiz