%loc = %BID.getPosition;
%radius = %BID.getDestructionVolume;
These are functions, not variables. So they should be like %loc = %BID.getPosition();
For the radius search just do:
%mask = $Typemasks::PlayerObjectType;
initContainerRadiusSearch(%loc, %radius, %mask);
while(isObject(%player = containerSearchNext()))
{
%player.burn(1);
}
The while statement will cycle through every player within the radius and run the code inside on each player. Starting with the closest player and ending with the farthest player.
containerSearchNext(); returns the next player in the list.