SEE ALSO: Lee Da Eun reveals text messages with late Kang Ji Yong's mother following family dispute

In the last episode of 'The Unit' that aired on February 10, a group of contestants was training with Jo Hyun Ah when they suddenly started screaming in terror and quickly left the room. Their mentor, Jo Hyun Ah, who didn't know what was going on, panicked and started running for the door as well until she fell down losing her heels. Jo Hyun Ah mumbled�to herself in confusion, "What's going on?"

The mystery was soon solved as the idols walked back in with a cake to show their appreciation for all the hard work and support their mentor has given them throughout 'The Unit'. The girls the gifted her a bag made out of Choco Pie and Pepero while saying thank you.

What a lovely surprise from the girls!