The veil is a barrier that separates our world from a parallel realm, in which demons inhabit. This veil prevents one reality from bleeding into another, although their our occasions in which demons can sleep through the barrier when it is weakened enough. The Aztec empire is a large civilization that practices human sacrifice, and seeks to harness the energy from the demon realm for their purposes. These sacrifices are done by cutting the heart out of an individual one after the other. By weakening the barrier, they can summon demons across the veil to enslave.
A violent act such as a murder can cause a slight ripple in the barrier, causing it to theoretically weaken. The ripple from a murder is too weak to open a passageway. The Aztecs must cause a large sacrifice through a ritual in order to weaken the barrier enough for the summoning to be effective. But there is another problem. The ripple caused by each murder lasts less than a nanosecond, and is not long enough to weaken the veil to be useful. By the time the next sacrifice is made, the effect from the first ripple has passed, rendering it useless.
For summonings to work, individuals must all be sacrificed together. These deaths must occur at the exact same time, down to the very second. This is an issue. If the priests are even slightly off, the ritual fails and the sacrifice is waisted.
Is there any way to synchronize their efforts to make this ritual work?