Originally Posted by
DoctorCopper
If you are both airside, then one of you popping outside to smoke hourly isn't going to be a viable option. Doc Copper
I agree, and if the staff in T5 becomes aware of it, they won't facilitate it either. By all means go out and stay out, maybe building that into the connection process, but the whole process could easily take 30 minutes end to end, so you can see why it's not plausible to do this too often.
One option, if you have Priority Pass, is to use the lounge at the Sofitel instead of airside, then pop outside the hotel for the narcotics experience, before entering T5 airside an hour or so before departure.