One little sentence was all it took to plant a seed of doubt - he'd said so himself. And, once that seed was planted, all it took to allow it to grow, to spread its roots, was time to think. Time to mull over things, perhaps a few more little words to act as fertiliser, to speed the process along. Sebastian was perfectly ready to tend to that garden just as he tended to the garden within the grounds, easily dropping what could be seen by anyone else as a joke, whispering to the Earl about betrayal and corruption moments after shielding him from the flying shrapnel caused by yet another of his chef's attempts at cooking.
The little mistake, not uncommon, slowly became more in the child's twisted mind. The trust he had in the veteran faded, and his presence made his master uncomfortable, edgy, snappy. He couldn't take it anymore. This was his home, his manor, he was not meant to feel threatened here.
His friendship with Mey-rin and Finnian was no longer worth keeping him alive for. After all, for all he knew Bard would just as easily try to kill them, or Elizabeth, or Aunt Frances, or Uncle Alexis, or Edward, or… anyone. Too many risks and a traitor wasn't worth it.
And so, the Earl, restless and taunted by nightmares and voices, had risen from his bed, pulling the pistol out from under his pillow and making his way quietly out of his room, down the hall, the stairs, navigating his way to the servants' quarters where he began checking each door - the manor, after all, had been built to house more servants than the six he'd hired throughout his time as the family head.
By the time he eased open a door that bared positive results, the child was shivering from the chill, his own thoughts and the voices in his head given enough time to make certain this was the only way he could feel safe again. The chef was asleep in his bed, Finnian, Tanaka and Snake in similar states of rest in the small room - but Ciel's mismatched eyes were only fixed on the tallest of the blondes.
Squeezing through the gap in the door, the young Watch Dog crept towards the end of the bed, feeling his heart race with anxiety - the man could be waiting, prepared for him. He had to do this quickly. Before the man had a chance to even awake.
Tightening his hold on the loaded gun, he lifted it, aiming carefully, right for the man's temple, and squeezing the trigger. The sudden break in the silence and interruption to the incessant ringing in his ears made the boy jump, the startled spasm making him drop the gun as the other servants stirred to find their friend dead and the beginnings of relieved laughter on their Master's lips.