HELP WITH MY ATIEL?

Ive had my atiel almost two weeks now, he is just under 5 months and very scared, hes settled in and receives so much attention from me its untrue, but is still weary of other people and sometimes me. He takes treats through the cage bars but as soon as i try to touch him he hisses or bites, there are a lot of people in my house so a lot of gazers, does this matter? I tried to open the cage and leave him to make his own way out, but he didn't come out, help on what to do next ASAP please!!!