i'm applying for a job as a security officer and i'm not sure how to answer this one on the application:

'while doing rounds at your account a man approaches you.  he informs you that his elderly wife has fallen down and may be unconscious.  as you approach the scene you observe the woman is lying face down.  you are the only security officer working on that shift.  what do you do?

i'm thinking to first check and see if she's even alive and then contacting the hospital via 911 or something..but i'm wondering if there's more to this question like if the guy had done something to this woman..

You are on the right track.

Check her first, apply first aid if you are properly trained, then call 911 or have someone else call 911 if you are 10-6 on first aid.