In the Olivet Discourse, for example, Jesus mixes in the destruction of Jerusalem and the tribulation before his second coming, without clearly separating them. When John speaks about the antichrist coming, he also notes that many antichrists are already in the world. Partial fulfillment again. Such action would be viewed as much as a warning of bodily harm as actual damage to the property. So it is with biblical prophecy.
Partial fulfillment indicates that more is to come.
The key element that was fulfilled on the day of Pentecost was the coming of the Spirit. Notice the repeated mention of the Spirit throughout the prophecy. All this was designed to show that the old covenant was now done away via Christ's first coming. Not at all, if we are to see other biblical prophecy fulfillments as a guide. This is a point that the rest of the NT authors are united on and still continues to this day.