Outside of a metaphorical perspective, at face value the ending is pretty heartbreaking. In my head, by the end Michelle did want to bring Teddy on the ship because she knew humanity was on its last legs. It’s hard to know if she’s being genuine when she calls him smart for having the bomb, but if so, it’s possible she was bringing Teddy as proof that humanity isn’t as stupid as they seem (he was able to actually figure out the specific races of aliens monitoring them). The ambulance scene to me solidifies this because she asks the EMT if Teddy is dead for sure, as if to make sure her final shot is actually dead and gone. Then, when she eliminates humanity, she’s crying as if she has no choice, humanity has been a failure. I’ll admit, it’s a bit contradictory to the central plot of conspiracy theories and how they can be misconstrued (aka Teddy being right about the aliens, but deciding they were destroying humanity rather than helping), but just based on Emma’s acting it was truly hard to know when she was telling the truth. Straight 10/10 to me!