In the film Arrival, there is a scene where
a bomb goes off inside the heptapods' ship, eventually killing one of them.
However, since we find out later that
heptapods can see the future (and on Earth to prevent a catastrophe that's 3000 years away)
couldn't this event have been avoided? As far as I can tell, no one other than Louise ever learned the extent of the damage, so even if the event was part of the aliens' plan I don't understand why they didn't do a better job keeping everyone safe.
Relevant scene from the screenplay (though I'm not sure if it's the exact same as what appeared in the film):
Where is Abbott?
Costello moves the ink around with one appendage and a new logogram forms.
SUBTITLES: "Abbott is dead."
Louise holds her stomach, she's hit so hard by this.
I'm sorry. We are sorry.
The logogram ink shifts again. Louise looks down to read it.
SUBTITLES: "Abbott chooses to save Louise and Ian."