Lawrence singing "The Man Who Broke the Bank at Monte Carlo" in a canyon and enjoying all the echoes... only to realise someone else was watching/listening the whole time.
After getting his new Arab clothes, Lawrence (out of sight of the camp, and thinking he's alone) takes a moment to strike a few dramatic poses and admire his reflection in his knife. Then he spreads his arms like wings and starts running around... once again, only to realise he's being watched.
Auda abu Tayi: What are you doing, Englishman? Lawrence: As you see.
Auda offering insults:
Auda: Give thanks to God, Brighton, that when He made you a fool He gave you a fool's face.
Lawrence enters a military bar in Cairo with his Arab servant, ignoring the racist looks being given to them as they order their drinks....
Lawrence: We want two large glasses of lemonade.
Bartender: Th-This is a company of British officers!