You're probably fine to continue taking the elevator, in that case. But practice as much safety as you can - bump the elevator buttons with your elbow instead of your fingers, be sure to wash your hands before leaving your home, and before starting anything after you arrive at your destination. It's impossible to be 100% safe, but you can absolutely take proactive steps to limit your exposure and reduce potential infection, or spreading infection to others. Handwashing and social distancing (remaining 6 or more feet away from others while out) is critical.