I cut and pasted all your suggestions into Word, then tried to mash them all up. I tried to focus on the important things: 1) wakes up early, 2) murder!, 3) consequence. I felt that the sentence would be tighter/shorter by taking out the parents, but then that seemed to lose some of the threat to me, so I decided to keep it. I'm still not comfortable with the length of it, but I know that this is miles better than before-- SO THANK YOU ALL FOR YOUR HELP!!!!!!!

Edited with an (even further) updated version:

After waking up decades before her cryostasis was supposed to end, seventeen-year-old Amy must stop a murderer from killing the other frozens trapped on the space ship before her parents are unplugged.

I am absolutely not opposed to rewriting again, so feel free to rip this sentence up, too! :)

Ironically enough, your comments have also inspired me to entirely rewrite my query letter too! I am going to create, essentially, two pitch sentences (one for each POV character, as this story switches between them), and use that as a launching point for the query summary. Even if I don't end up placing in the pitch contest with this sentence, I'm thrilled that I now have a stronger query just because of the help you all have given me this weekend!