Loyalty
Schuldig taunted, pushed, challenged Crawford and his authority as intensely and as often as was practically possible. He talked back, ignored orders, messed with the others' personal possessions and annoyed the Hell out of everyone in Schwarz's household.
But once outside the barriers of their not so little home, just as an actor takes off and puts on a mask, he would obey his leader without hesitation, turning all his defiance, all his aggressive insolence to the world outside.
The change was so complete that not even his teammates could be totally sure who was the real Schuldig, and who was the persona he pretended to be.
But Crawford knew. It was his job, after all.
For that reason, when even the ruthless telepath had asked him one day how come he put up with him, Crawford had just reached out to carefully graze the pads of his fingers against Schuldig's cheek. The bruise left by the golf club had faded ages ago, but the Oracle had impeccable memory and his touch hovered over the exact point that had taken the blunt of Takatori's attack. At that time, the stupid pig hadn't been aware that the only way he could have ever touched the redhead, was because Schuldig had allowed him to. Under Crawford's command.
Still waiting for a verbal response, it took Schuldig a while to make the connection and get Crawford's subtle reply.
When he was sure he had made his point, the American just smirked and turned away.