Accessing Quinn's system was something that he could still do, but that made sense in his mind, since the system was a part of Quinn. It had been with him since he had become a vampire, and honestly without one knowing the equivalent exchange ability, there was perhaps no way of removing it.
Not that he would want to do so anyway. In the first place, it had done him more good than not. However, this was why he was slightly confused by receiving a message while he was here. Quinn's system was kind of connected to the celestial system, in a way,
It showed his celestial level, and the quests were linked as well. One of the things that currently was on there, was a type of quest, although it was more of a message than a quest.
In order to unlock his new skills as a celestial, Quinn would need to enter the celestial space. Which was why he believed the place he was in right now wasn't the celestial space, even though it felt like it.