Some fun thoughts to ponder
1. Does anyone think that the rule that the Nasghasts will kill anyone who even intends on harming an astronaut applies to the Nasghasts themselves? If it does apply to them as well, then Dr. McNinja could take a few different routes to worm his way out of things, since they are intending on harming him, a former and now current astronaut. If they exclude themselves from the rule, then:
2. Does anyone think the rule that the rule about even intending on harming an astronaut excludes astronauts? Because if so, Dr. McNinja never had anything to worry about, since he's been one since Punch Dracula, and the time traveling Chuck might not have known about this.
Of course, there's a lot more holes that can be pursued than just these, but these ones are the ones I think are the most promising cop-out avenues. Will be interesting to see if these issues pop up in the future.