A horrible accident happened while a pilot was walking with his paramotor. It was idling but, at some point, possibly after powering up to warm it up, the throttle stuck at a high power and he lost his footing, falling mostly sideways then face down. It went to nearly full power and his throttle cable got sucked into the prop, pulling his hand in and severing the cable. With no kill switch he couldn’t shut it off and his hand got chewed to bits.
By far, the best solution is to make your paramotor resists the possibility of the throttle cable getting to the prop. That will usually be as simple as a well placed wire tie holding the cable to the fame in a way that makes it impossible.
In the meantime, consider this:
Now look at this solution:
Check your paramotor to see if a change of throttle use is warranted.