Cocaine overdose is a very real threat to heavy users or those with pre-existing conditions such as heart defects, high blood pressure, or thyroid problems. Combining Cocaine with other drugs (especially other stimulants) increases the risk of overdose. Overdose death occurs from cardiac arrest.
Acute withdrawal is another very real problem for Cocaine users. When a coke user crashes, he/she often becomes demanding or confrontational; often, he/she remedies this situation by using more Cocaine, which is exactly the wrong thing to do, as it makes the next crash an hour later even worse.
If snorted, Cocaine will cause damage to the nasal passages, and if smoked, it will cause damage to the lungs.
As with many stimulants, Cocaine can incite acute paranoia in users. This is particularly an issue with coke, given the added dimensions of aggressivity and megalomania that can result from the use of the drug.
http://www.dartmouth.edu/~healthed/groups/dapa/otherdrugs/coke.html
. . . Lucy, who understands the hired help will be thrown under the bus, first.