Why were there two extra pilots aboard during the attempted flydubai hijacking?

I wondered yesterday when I learnt of this in the news for the first time. Was it just a lucky coincidence that there were other pilots on the plane?

Why were there two extra pilots aboard during the attempted flydubai hijacking? | The Jerusalem Post "The additional pilots were added to the flight because possible regional rerouting could extend the journey and push the original crew beyond permitted duty hours."