i'm gonna throw my blind guess into the ring since i'm concerned about my meth injection too.
I wonder if there were poor atomization and the water part of the 50/50 boost juice is pooling in the intake manifold. When you accelerate for extended period of time, they are sucked to the back of the manifold (cyl 6 intake).
I wonder if 100% meth would've prevent this pooling because they would evaporate quicker.
on a side note, isn't vishnu's PWM uses boost switch to turn on/off the pump already? or is that not the fail safe that people are talking about?