When you were messing around in the back room earlier, did you try changing the thermostat?
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.)
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.
There is a good hidey hole here in the back room. Have you found the "computer main" niche? That's the spot.
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.
Ready? Okay, here's the steps.
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!
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.