When you were messing around in the back room earlier, did you try changing the thermostat?
Hint 2
If you turn the heat up over 80 degrees or down under 50, a loud alarm goes off and Ewan comes in to yell at you. (Well, the first time he yells; after that, he boots you out of Scotland.)
Hint 3
What would be ideal would be if you could turn on the alarm and then hide somewhere; then he'd think the heater was just broken on its own and stay there to fix it without blaming you.
Hint 4
There is a good hidey hole here in the back room. Have you found the "computer main" niche? That's the spot.
Hint 5
You might want to find it before you start, because once you change the thermostat you only have 10 seconds real time to get there before Ewan catches you.
Hint 6
Ready? Okay, here's the steps.
Hint 7
Turn the heat up to 80 or down to 50. Immediately back up twice, then go left, forward, left, and look for a CURVED right arrow. That's the "computer main" niche. Whew!
Hint 8
Stand there and wait for Ewan's footsteps to go past, then go back, sharp right, and forward to go back into the main room.