Totally agree - if you aren't too familiar with this lounge, the "terrace" is a (usually) quieter "outside" environment (outside the four walls of the lounge, but still within the actual terminal). Less chance to be disturbed, but set your alarm so you don't miss the connection!

Or - if money is less of an object - you could get a Day Room at the T5 Sofitel, which is connected to the terminal.