"John Lemon tutorial" eating up my CPU

Hello. I am super new to Unity (just got it yesterday actually.)

I've been following the "John Lemon's Haunted Jaunt" tutorial and made it as far as part 3 "the environment" when I noticed a terrible lag I ran the profiler (which I still dont' really understand how to use) and like i suspected it's completely overloading my CPU.

Running in play mode and after just a few minutes of walking around my CPU is at almost 100° celcius.

I have a Macbook Air, 2 years old, Quad-Core Intel Core i7

I knew Unity would probablybe CPU intensive but I didn't think a simple beginners tutorial running for a few minutes would melt my CPU like this.