In a remote location your survival chances are quite low if you don't seek help. I have been thinking of doing this in the winter. The method will have more success if you use alcohol in combination with the lorazepam. I personally don't think you'll be able to stay asleep as you get really cold, but i'm not sure.
Alcohol will amplify the effects of the lorazepam, but will also make you feel warmer than you are.
From wikipedia:
"Alcohol consumption increases the risk of hypothermia in two ways:
vasodilation and temperature controlling systems in the brain.
[29][32][33] Vasodilation increases blood flow to the skin, resulting in heat being lost to the environment.
[32] This produces the effect of an individual
feeling warm, when they are actually losing heat.
[33] Alcohol also affects the temperature-regulating system in the brain, decreasing the body's ability to shiver and use energy that would normally aid the body in generating heat.
[32] The overall effects of alcohol lead to a decrease in body temperature and a decreased ability to generate body heat in response to cold environments.
[33] Alcohol is a common risk factor for death due to hypothermia.
[32] Between 33% and 73% of hypothermia cases are complicated by alcohol ."