As they approached Lucy's place, Mirajane had always heard around Magnolia that Lucy seemed to do 'dangerous' things while on her way back home, so the swinging orb happened to take that same route the blonde always procured.

"Ohh, see the ball Lucy? It's acting just like you do on your way home...don't lose it! Keep your balance, and make sure you don't fall." she cooed into Lucy's ear while watching her with an eager look in her eyes.

When they finally did make it, Mirajane allowed Lucy to lead the way with the orb going right toward her bedroom and continuing to swing as it approached the blonde's bedside.