That's probably because of Tim's experience as a teacher. A good teacher will lead a student to get the answer for themselves instead of just giving it to them.
That said, this isn't school, so I don't really mind Christian's mentoring style. I laughed when Sonia's model tripped and Christian was all "I told her so." He definitely keeps it real.
Overall, I enjoyed the episode. I was pleasantly shocked by the lack of whining over having to camp and work outside. However, I miss the genuine unconventional challenges that took place in real-world settings, where the designers were let loose in a grocery store, hardware store, candy store, etc, and had to use only those materials. For the last several seasons, they've given the designers a pile of materials chosen by the show. It seems boring and canned compared to the "in the wild" approach, and the designers don't have to be as innovative.
I would have liked it better if they had spent one day hiking and camping out and then had to dismantle their camp site the next day and use only the materials that had actually been part of the site, instead of "here's some random stuff associated with the outdoors."
I'm glad the winning look actually followed the challenge and no one whose model was cold won. Yes, technically anything can count as outdoor wear--you can even wear your birthday suit outdoors!--but the spirit of the challenge was to come up with something that could be worn camping--or at least glamping--in the woods. How does living and working in 40-degree weather inspire you to put your model in a bikini with some net over it?