 It seems unlikely to me that the disciples of Jesus had much of a clue about what was going to happen on this day. They don't seem to have had that much insight at times in the ministry. He told them, stay at Jerusalem now, don't go home, because you're going to be endued with power from on high not many days hence. They might have had some idea about that, but what happened on this day had to be a bit of a shock.