Clara and Akito arrive to clean up. Not exactly on time, but barely just enough to see him teleport back to Earth. So it really is becoming Clara vs Juliana with extra steps. I don't think best girl is in the mood to be forgiving. Not for this wannabe homewrecker trying to steal her man, and making her go on a wild goose chase around the world to save him.
It's not so much that they arrive barely in time to "see" him teleport back, and more that they arrive in time to cause him to teleport back. She "un"summoned him (dismissed the summon? However one would phrase "sent him back")
Also, with regards to the impending "fight," Clara is an important noble from her country, the other woman is an important noble from a different country. I don't remember their exact designations, but I vaguely remember that the other woman (who's name I can't remember or be bothered to look up) is of HIGHER standing than Clara.
Why does this matter? If Clara
kills her it could easily cause an international incident, up to and including war. Even if they don't let any of her people escape to report it, there were still people on the ship and massacring them would be in public... Additionally I have no doubt that the "other woman" notified her homeland that she was returning, and Clara obviously notified her homeland that she was going after the MC. The country can easily put two and two together.
Doesn't mean she
wont kill, but she might hesitate.