Use a text editor to edit the "user.ini " file in the "system" folder in the game's directory. Change the following lines:

DamageModifierMedium=1
DamageModifierEasy=0.25
DamageModifierHard=1.75

into:

DamageModifierMedium=0
DamageModifierEasy=0.0
DamageModifierHard=0.0

Note: You (Boss) will take no damage, however your team will still takes damage.