Hi I'm new here.
I agree that karma strikes back for K/J. Also, I think that K/J were not laughing at Luke. She smiles everywhere. Yeah...
Karma is really ready to get back at Jen in EP10! EP9 quite clearly shows Jen say that this far into the race she is getting competitive and something about "if she sees someone in front of her, she is going to knock them over". Then later on, after the smackdowns, in reference to M/L, something "pissing them off more, cause I will laugh in their face". Very unChristian attitude on Jen's part. I know this is a race, but.....
Luke is not an angel in EP9 either. He is clearly is ready for payback and gets out of control. However, you can clearly see how mad he is at the mat. His face is so red! He has been a little whiny here and there, but he has certainly carried his weight in the tasks.
My reading of the action at the first clue box is that Jen lived up to her promise to "knock them over". Luke leaned over the clue box to open it and Jen ran into him, then got upset when Luke tried to fend her off.