No, DR Jennifer, the first scene in MEDIUM was Allison waking up, laughing a bit, and then assuming she had gone home with this strange man for the evening. We only found out in bits and pieces that she was "Sandra," but there was no dream before she woke up.
And no on the second point you asked about as well. At that moment, it appeared foir a second that she was back to normal, but we didn't see her planning to trick him. The hospital called Joe to say that his wife was asking for him. and we thought she was well until we saw her sneaking away while he was filling out paperwork.