As Jin entered the Virtual Reality Instance, his body flopped in real life since his consciousness had been uploaded into the System's database. The first iteration of the VR headgear had been a little choppy in terms of transmission. One of the bugs had made the transmission so patchy that Jin had been losing parts of his body whenever he walked inside the Virtual Reality.
The System thought it was funny to look at the sight of Jin panicking at the data packet losses of his body and even took some screenshots for posterity. For the second version of the VR headgear, Rei had been able to smooth out these kinks. But even though Rei was the overall engineer for the VR headgear, the one responsible for the much smoother uploading of consciousness was none other than Starry Mood.