So did the humans of the Fleet, especially with the evidence that it- Tallos, as Baltar had named it with his sense of aptness- might still have some will of its own.
Though Baltar believed he'd straightened out that problem, Commander Adama still worried.
To test his worries, he had the human Cylon they knew about (the instance of the Number Eight model that Helo and Starbuck'd brought back with them from Caprica) taken out of the brig and put before Tallos, so that they could see if the reprogrammed Centurion would obey human orders even when another Cylon was there.
The moment Tallos saw the one Helo still called Sharon, he broke his bonds and threw aside those around him.
( Everyone reacted unsurprisingly. )