On my experience of Airbus ground running above reply is correct, opposite engine EPR/N1 should be raised to balance, this power is usually above ground idle.
With regard to running with cowls open, this should not be done as you are compromising fire detection and or fire extinguishing systems, dont get me wrong I know it happens but me personally I would always have them closed.
Back to the engineer death, the only way to completely eradicate this from happening is to have engine cages at every airport. Due to costs and time involved in using these this will never happen. Sad when time and money is put before human life.
