That’s probably not safe to sit on, just saying

Yikes, that's a death penalty. The crime? Leaving the cereal box open to get stale.

As someone who has operated such machines before, there are ways to render it safe..."safe-er"

drain out all the gas, turn it off, remove the spark plug connection, place a sturdy lid over the opening... Even then it is not advisable, but safe-ish.

The blood, however, is likely someone missed the safety checks... All of them.