Okay, I'm only going to say this for the perspective it gives. I'm not bragging, but I have 11,000 hours of helicopter time over 35 years of flying. The point of saying that is to note that that amount of flight time comes with a ton of time sitting on the ground at idle. Over the years and hours, I have NEVER had an idling helicopter do something weird or funky where I had to grab the controls and do something. Not that moving the controls would do anything. The way the control system is designed, if a blade flaps but the swashplate does not move, that blade comes back pretty quickly to its original plane - it doesn't stay deflected. There have been times when I grabbed the controls in fear, like when a larger helicopter landed beside me. But in every instance, there was really nothing I could do - maybe slam the throttle up to full, but that likely would have been a futile case of "too little, too late." Nor has any idling helicopter spontaneously caught fire or exploded on me. The only advantage of being inside a running, idling helicopter is that the parts and pieces will all probably be flinging away from you if it all comes apart. Your experience may be different, but I've never had a case where something happened and me being at the controls or not would've made a difference.
Have I ever gotten out of a running helicopter? Oh yeah! Sure, of course. Every helicopter pilot who doesn't exclusively fly out of nice, paved airports or heliports probably has had to get out. We cannot always shut down and stop the blades at every interim stop on every multi-leg flight. And, while I understand that opinions vary wildly on this, there's nothing inherently unsafe about "getting out while running." You just have to make sure you're on solid, level ground, make sure the engine is at IDLE, make sure the controls are frictioned/secured, and (if you're in a 407 with boosted pedals and you're stupid enough to leave it up at "fly") make sure not to leave an iPad on top of the dash that might fall off and hit the left pedal. If you do al of those things, you (and your helicopter) will be fine.