Pertaining to this video clip, I felt that it is fake..You will decide yourself after watching it..
1) Look closely, there is motion trail on old lady..
2) Judging at the reflection of light in the lift, the lift door closed before the lady reached the door..
3) Look at the metal handle inside the lift, at timing of 00:27:48:15 - 00:27:49:05, you can see some light pop out and fade off. The same thing happen again at time 00:27:57:00 - 00:27:59:22. The "light" is at the same position at the shoulder and head the old lady when she appeared...
4) Funny thing happen at 00:28:04:22, when the 2 guy entered the lift, there seem to be some distortion in clip.
5) The lighting inside the lift became dim and brighten up again between time 00:28:09:12 - 00:28:09:22.