Felix knew about Apollo's dormant wisp within him and he even brought it with him inside Asna's core.
He refused to wake him up because he understood that Apollo's darkside could not be trusted. While he had helped him out many times, he didn't do it out of the kindness of his heart.
He wanted something from him and Felix had no interest in playing along unless he was comfortable with his requests. Thus, he planned on keeping his wisp dormant until he was strong and comfortable enough to meet him.
Even if he knew his attitude had caused Apollo's darkside to assume his betrayal, Felix would still have done the same.
Right now, all he was focusing on was catching up with Asna, perfecting the plan to kill her, and reviving his soul.
Meanwhile, Quantix Prime, Commander Bia, Darkin, and the rest of the Vibronxian Empire's troops had long embarked on their journey towards the Echoing Tower's ruins.