Evie wanders off in the middle of the city. Part of their group is like, "She's a very nondescript human girl, it's gonna to be difficult to locate her."
Sai is like, "Excuse me, ma'am! You didn't happen to see a teenage girl about this tall, have you? Brown hair, probably kinda spacey expression. No? How bout a six foot tall albino guy wearing a long jacket with the taskforce logo? He was probably following said girl."
They find the duo within 10 minutes. Zero is kinda hard to miss, even in a crowd. He also follows Evie around like a puppy when they're outside the base. (In certain parts of the city, his concern is definitely warranted.)
Sai sometimes attracts attention 'cause of his eyes and his hair color too, but he's shorter and slimmer than Zero. It's easier for him to blend into a crowd if he's wearing a hoodie. The Constructs are partially human, but Sai was made by aliens. Not the invaders. His creator is from one of the groups that allied with the humans. Sai and his sort look a lot like the Constructs, even though the aliens don't resemble humans much. I dunno if that means they're genetically engineered human/alien hybrids andcyborgs or if the similarities are purely aesthetic. Or if it's more complicated than that.