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The pulse is an unknown shockwave found within the mines. It occurs approximately every six seconds, and the only warning given before each wave is a distant flash of light and a build up of bellowing wind. Objects in front of the wave will be violently blasted away, including the protagonist. Sturdy objects and walls are the only methods of protecting against the pulse.
The pulse is located within the mines, which is Sector 2 of the facility. It is found in a massive subterranean cavern, large enough to have its own shoreline and beach. The cavern's entrance and interior contain mining equipment and work stations, along with remote albinos dressed in work clothes, suggesting that the vast atrium which holds the pulse was mined out.
The gate to the atrium is only able to be accessed if the weight of twenty individuals is placed on a pressure-sensitive plate. The protagonist completes this by controlling the various mining workers around the area to follow him.
The atrium's initial area contains sandbags and still-functioning construction equipment as the protagonist progresses, alongside mechanically manipulated blast shields, of which, several seismometers can be seen nearby.
According to many theories, the pulse was designed as a failed sonic-based/seismic weapon. This theory is supported by the presence of multiple bound crash test dummies in chairs, and a man-portable blast shield that is able to be used for deliberate protection against the pulse. Also, the fact that the pulse can hurl objects, such as barrels or boxes, at speeds that can damage concrete indicates that the pulse is most likely a mass destructive weapon.
Another possible theory is that the pulse was used for mining rock beds like the one seen before reaching the atrium. However, the pulse does not indicate any ability to break apart rock or metal, making this theory only plausible at best.
- The music that plays during the pulse is synced directly with the coming and going of the wave itself. During the second half, the music changes from heavy wind sounds to an electronic rhythm.