As the window open I release everything that corrode inside of me
He throws up, releasing the alcohol and drugs he had taken.
Symbolizing the pain and negativity that has been brewing up inside of him, only being aided by the consumption of constant alcohol.
As suggested by the previous line, he is smoking. Rolling down the window is to let the smoke out. As soon as the smoke comes out he feels relieved of all of his stress and worries.
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