tech errors transfusion of incompatible blood

I would say no to firing. This is a system error. The system needs elements and steps to follow (checks and balances) prior to the issue of the unit. The second tech's errors were probably more severe than the first. Why wasn't the IS XM done? Is it behavioral issue? I'm suprised the FDA hasn't appeared. You should report it. If ever you needed a justification for a computer system, you have it. Have you considered documenting the retypes on a separate sheet of paper or log sheet? That way the line above would be no influence to the person doing the retype.