Luke had seen too many similar setups in movies and TV shows before. When he noticed Ellen, he had adjusted the surveillance range beforehand.
The camera had an infrared function to monitor the lake 24/7 in case students snuck out for a swim and got into trouble.
Of course, it was Luke who suggested setting up the camera, and who provided the device.
He didn't charge the school a fee for it, and would just take back the surveillance equipment once this assignment was over and both he and the students returned to Los Angeles.
It wouldn't be easy to convict Ellen with the camera footage, but if the Elsworth family planned to set Luke up later, the footage would be great evidence to prove his innocence.
After the unannounced guest was driven away, Luke's agenda was clear in the afternoon.
On the third day, the teachers took the kids to a nearby mountain to teach them the basics of surviving in the wild. They also had to cook for themselves.