I called Electromotive yesterday and asked this question. They verified that it is a series circuit, but could not explain why the current flows from a grounded engine. They also confirmed that the coil will fire spark plugs separately, but that the coil is not firing correctly and this will ultimately damage the coil.
I agree with tinypanzer that is must be that the negative side of the coil has more potential due to the voltage or something of this nature. I was going to try and contact someone at the university that could answer this.

I also wanted to mention that the idea of removing the resistor end on the spark plug wires and installing a resistor plug was mentioned by the gentleman at Electromotive, but that resistor wires should still be used. This applies to standard plugs though and that this is not necessary with the iridium small tip plugs. I will leave platinum out of this.