John was n't sure she had an appointment , or was even in her office , but he found himself in front of the door at 1700 . For the life of him , he could n't remember what time the concert was tonight . He hoped it was n't too soon ... He had told Colleen that he would be late tonight and that he probably would step in , get something to eat , and then go back to the shuttle bay . She had said she would probably join him at some point , and leave Keith with Saril .

Question: What 's a possible reason John could n't remember what time the concert was ?
Answer: Because John found himself in front of a door .Because John is forgetful .Because he hoped it was n't too soon .Because he told Colleen he would be late .