What happens if a non-diabetic receives an injection of insulin?
Blood sugar drops (Hypoglycaemia)
There are several other uses of insulin (other than diabetic treatment) 


Some of those could be: 


Diagnostics
Psychology (Narcoanalysis)
Parenteral nutrition
Cardiology (Glucose–insulin–potassium solution (GIP or GIK solution) is given   after a myocardial infarction)
Malignancy (Insulin potentiation therapy (IPT))
Psychiatry (Deep insulin coma therapy (DICT))




Sources:


Niazi, Asfandyar Khan, and Shaharyar Khan Niazi. "A Grand Dame
with Hidden Aces: The Non-diabetic Uses of Insulin." Indian Journal
of Endocrinology and Metabolism. Medknow Publications &amp; Media Pvt
Ltd. Web. 06 Feb. 2016.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3354952/.
"Hypoglycemia." Hypoglycemia. Web. 06 Feb. 2016.
http://www.niddk.nih.gov/health-information/health-topics/Diabetes/hypoglycemia/Pages/index.aspx.