RE:THREEI think you missed the plot line.
The three engineers worked for AMEC. They were negligent in designing the tailings pond. The regulatory body for professional engineers is disciplining the three engineers for their unprofessional design work.
Imperial is currently in mediation with AMEC.The mediation will determine how much is owed by AMEC to Imperial for the unprofessional design work, which resulted in the tailings spill.
They are not Imperial's employees, and have no claim against them.