if one fails to be there for a portion of the required time...
if one fails to be there for a portion of the required time, one's Hajj is not invalidated. There are two types of stays: Wuquf al-Ikhtiari (Optional stay): Stay during the day time. Wuquf al-lztirari (Compulsory stay): A short stay on the Eid night. If for some valid reason or lack of knowledge one does not perform Wuquf al-Ikhtiari then she must do Wuquf al-Iztirari and her Pilgrimage will be valid.
There was a tent city in the plain of Arafat, the artificial lights were shining, but here it is just open space with dark of night on all sides. Yes as one rite of Pilgrimage follows another, it becomes simpler. The pilgrim starts feeling closer to nature closer to his Creator. Meaningful thoughts and inner light make him aware of the meanings of his creation. The meaning of Mash'ar is awareness or perception. We can say that Arafat was one grade and Mash'ar is a higher grade.
That grade we attended in the day time and now we are in the night class. Both classes are held in plains. In the first class there was roof to sit under, food to eat and lights to brighten the surroundings. But the second class is held in a plain where there is no food to eat no lights to guide one. There is a danger of getting lost. Pebbles have to be collected. The pilgrim is already very tired.
Yesterday in the plain of Arafat hands were holding supplication book, now hands are full of pebbles which will be used for attacking the enemy. Oh! The pilgrim of the House of Allah (swt) if you have been lacking in deeds, do not stay behind in supplication. If back home the world, friends and foes, neighbors and co workers, teachers and class mates distracted you here there is no one to do so.
The Greatest Host has brought you to this land where the earth is full of tears of all Holy Men of history. The atmosphere here is witness to the grieving and crying of passionate followers of Allah (swt). Be appreciative of this Holy place and wake up from your slumber.