You have to do the quest... Keep doing the quest. 1. take the quest from Susan 2. put pills in Rachel's drink at midnight. 3. (sleeping pills only work for 1 day) - disable her alarm clock the same day you had her drink the pills. 4. turn in the quest for Susan in the morning.I keep trying to but during 20:00 they are never in her room
It is easy to miss a step and it will seem as though you are stuck. Just run through it all see if you missed anything. Most likely is that you take the quest from Susan (so she won't offer it again you already took it), then forget to put the sleeping pills in Rachel's drink. Just put more pills and disable her alarm clock.