William wanted part of this grand loot for his future plans, and he wouldn't be stopped by such a lame excuse of being seen as a materialistic person, being greedy, or something like that.
When he arrived in the back room section, he saw a long corridor with many doors opening at it.
Through the slightly opened doors of some rooms, he found out that everyone inside was in deep sleep.
At this moment, and through the opened windows in these rooms, he noticed that it was pitch black outside, and that meant he slept for a long time but still awoke in the middle of the night.
"I'll rest then," William excused himself when the butler led him to an empty room in the side of the long corridor, "I'm going to leave tomorrow, so I expect to get my reward before leaving."
"... Have a nice sleep," the butler knew if he lingered around for any longer, he might lose all respect for this kid.