The Rank 7 experts from the Cult of the Goddess and the Followers of the God of Fate didn't expect that a Rank 8 expert would have been killed so quickly.
Although it hadn't been a proper one versus all battle, the two that interfered were at Rank 5 and Rank 6, so their involvement shouldn't have mattered too much.
Based on the rumors about them, the others could consider that Shiba and Eini had the strength to rival someone at Rank 7, even kill someone at Rank 7 with a sneak attack, but their attacks shouldn't have been able to harm so much someone at Rank 8. Their attacks had been far more extreme than what the rumors said.
However, except Shire, no one else had seen Shiba and Eini combining their strength to fight after both reached their current levels, so the rumors were only considering the strength they had alone.