Seriously, lucina comes with spur atk, and shes not even next to veronica while veronicas attacking, where if she was, rein would die. Its not a hard concept, its just you going full retard.
But... That doesn't change the fact that he may not be running it on her. For all we know, he could be running Drive Atk on her with a +6 atk buff on Veronica and she's not killing. How would you know?
Dude you can literally see it in the picture. Veronica is selected and Lucina has the heart icon on her, they're ally supported. Lucina is 2 spaces away and Veronica is 1 damage short of killing. If she was 1 space away Veronica would have 1 more attack.