Final answer:
At a BAC of .45% or higher, one can experience life-threatening symptoms such as severe CNS depression, unconsciousness, coma, and potential for death, requiring urgent medical care.
Step-by-step explanation:
At stage 7 of the BAC Scale, with a BAC (Blood Alcohol Concentration) of .45% or higher, a person can expect to experience severe central nervous system depression, unconsciousness, coma, and potentially death. This level of intoxication can also cause respiratory depression, a critical decrease in heart rate, and a loss of reflexes. It represents a life-threatening condition and requires immediate medical attention.