Lisa was so worried about her friend that she didn't want to waste time, and entered her house, despite the gas. She noticed Rachel's (empty ?) clothes lying on the ground, and before she had time to search through them to see how much the young girl had regressed, she started to become younger herself.
From a 15-year old girl (She was younger than her friend), Lisa gradually regressed to a 12-year old, then a 7-year old, and in a few minutes, she was not older than 1, completely covered in her oversized clothes. However, since she was originally younger than Rachel, Lisa's regression continued until...