I was cleared to line up after Air Seychelles HM63 rolled for takeoff at Singapore's Changi International Airport. As the aircraft lined up at RWY20C, I looked up and witness a bright glow of orange color coming from the left engine of the B767
I'm confused
in the quote above I'm not sure whether the B767 was on the ground or in the air when you looked up. Your words "look up" could be interpreted as looking up from eyes lowered looking at your instruments or looking up into the sky.