The problem is that in novels he wasn't there. The whole scene was changed only the outcome is the same.
Now, since the idiot director decided that war is not that important, Saito and Louise don't have much to do so just kind of hang around just for the sake that they should be main heros (though they are not in anime, Anes is).
So again director put them in as a spectators just so that we would not forget that they exist. Yet this also made this scene weird, they did nothing at all though they could have (while in novels they couldn't do much about it because of the circumstances).
But again, don't look too deeply into this anime. As it strives hard to become the worst continuation of anime series this year, so let it slide.
They are doing their best to be the worst after all. You have to give them credit at least for that.