Fear of death
The sun was starting to set, which was the signal, saying it was time for the hunt to end. For Quinn, Fex and Linda, they weren't really worn out or tired. They could also fight just fine in the dark. However, the same couldn't be said for the others.
Although Quinn could use his Qi control to help out Dennis and the others in recovering, it could only do so much. If forced too much, Quinn was afraid that he might start to affect them badly. After all, he only knew so little about Qi, as Leo hadn't taught him much beyond controlling it.
After reaching the van, the Parasite members seemed to be overjoyed that both Wevil and Hana were still alive, and hadn't gotten injured. Linda took the wheel, and they were off again.
While travelling back, Quinn started to think about a few different things. Seeing how he was able to defeat so many emperor tiers without too much struggle, he thought it was a waste of time for Alex to make him a set of king tier equipment.