Time as we understand does not exist in the grave. Its part of this world but not of it.
Someone asked my teacher about how can the angel of death take different souls from so many people on the earth?
He said that the angel are made from light, right? Earthly light can travel from the earth to the moon in 1.2 seconds. So what about light is not known of this earth because the light angels is made is not like earthly light therefore faster.
So the angels travel faster than light, so there is no problem there is there. Cool!