With only he and Zodiak on the 6th floor, Arthur didn't encounter any problem and caught as many as 30 rabbits all thanks to the treant appearance, which didn't alert any of the furry and adorable white animals.
Moreover, as this forest is vast, he has not heard or saw any signs of fighting which can only mean that Zodiak is either far away or had already finished the randomly given quota. Unlike the rest, Arthur was not in a rush and wanted to wait a bit for Lucy just to see how she's doing.
Obviously, he's not going to openly interact with her, nonetheless, it wouldn't hurt to go a bit slow. He managed to catch thirty rabbits in half an hour, which equals to one per minute, a decent pace, or so he thought.
There was no warning from the system that other contestants have passed the 5th floor, meaning that 'Haven' is not as simple as it seems.