especially the fact that the hearts of these "dead" men were still beating is just crazy.

Not exactly - they weren't dead when their hearts were in fibrillation - often when people refer to a cardiac arrest what you have is ventricular fibrillation which means that the heart is flailing about in an uncoordinated manner. If it is isn't fixed death results within minutes.

I am wondering if their PTSD, which they all most likely all had, combined with male Testosterone ( I bet the only woman that died had higher levels of Testosterone too) and the DMT created during REM sleep most likely contributed to Cardiac Arrest.

They could well be contributory.

Maybe just like those "Gurus" that can slow their heart beat down with their minds, maybe these people "sped" up their heart rates to the point of failure just with the power of the mind.

Yes it is possible.

Awesome STORY!!
full steem ahead!

Thanks!