Can quetiapine withdrawal kill you? if so how? and is it more dangerous to take low doses than high ones?

Stopping quetiapine: No. Stopping quetiapine is not lethal. Stopping this medication cannot kill you. You mention you have social anx & borderline PD. When you stop or start a new psych med, you want to make sure you do this with careful instructions from your psychiatrist. You may want to schedule closer appointments for monitoring while meds are being changed. If you have questions, always clarify with your doc :)