The situation you describe, as far as I can tell from the code, can not happen.
- You can not enter Mrs. Taylor's apartment at night. At the point you describe, having Mrs. Taylor's keys, you can only enter at dawning (00:00 to before 06:00).
- There is no dialog anywhere that tells you Mrs. Taylor is sleeping when you are inside her apartment or when you try to enter.
- There is no code that, when you are in Mrs. Taylor's apartment, tells you that she is sleeping and then transports you out to the street.
I can only assume you are not being specific enough to describe the problem.
This quest is completely described in detail in
@ballzak's walkthrough in the
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. At a guess, you need to progress further with Sarah and/or Rachel, you need to give that photo to Ronald at school to get the promised Tinymon card, and then give that card to Sarah. The walkthrough specifies how far you need to progress with Rachel and Sarah to progress with Mrs. Taylor.