It looks like Clare was willing to make the sacrifice

I think he had to do the prep work because he was weakened in the crash. Then he had to find suitable kids to help him regain his strength, which took the amount of energy from a nuclear fallout, and then he needed to find a way to send a signal into deep space after his beacon was destroyed. (The rock) Then after that he needed to find a host and another way to send the signal. While all this is going on the humans are trying to stop him and becoming more of a danger to the plan, thwarting him alot. If he hadn't crashed in the beginning then the whole invasion/abduction probably would have happened alot quicker and no one would've known till it did. I personally loved the series and while there were things I hated like the whole affair subplot, I really liked it. It was a mystery and now is even more of one. I hope it gets renewed but am skeptical because of all the haters. Honestly if you don't like it, don't watch it. I think there should be a special channel that picks up and continues cancelled shows or does a movie that ties everything together and gives fans who want them their non cliffhanger happily ever afters. But sadly, the entertainment business is more into torturing fans than giving people what they want.

I think the light beam sorts of stuns or paralyzes them. Claire knocked Henry out of it, but then she was trapped by it.