Hi,
The images you've shown are for a slice file 1 m above the floor, and the maximum temperature is 270 C, not 150 C. At the risk of stating the obvious, it's much hotter up near the ceiling. :-)
If you load the other slice file of temperature (in the YZ plane) the maximum temperature at 196 s (just before the window opens) is 516 C. See below. Note that I manually set the maximum temperature range to 600 C to ensure that the problem wasn't the auto scaling of the temperature range.
Dave