In those cases, the spread between the bid & ask goes to the market maker as compensation for making a market in a stock. For a liquid stock that is easy for the market maker to turn around and buy/sell to somebody else, the spread is small (narrow).
In cerebral hypoxia, sometimes only the oxygen supply is interrupted. Brain cells are extremely sensitive to a lack of oxygen. Some brain cells start dying less than 5 minutes after their oxygen supply disappears. As a result, brain hypoxia can rapidly cause severe brain damage or death.
Delirium tremens may develop any time between 12 hours and 4 days after the last drink. The range of onset is fairly wide. There is, however, usually a window of opportunity consisting of the first 24 to 48 hours of detoxification. So even if your body is gearing up for a horrific case of the DTs, it will likely take at least a day to get to that point.