One SOG operative armed with a China Lake Grenade launcher fires all the rounds from his weapon. The SOG fire back and a firefight begins. As the SOG soldiers exit their hiding places, one HECU operative aims his M40A1and takes out a SOG operative.

The SOG members quickly scatter and and the rocket blows up non-lethally. One HECU member armed with a HECU RPG fires the rocket at the SOG operatives. Up ahead, six SOG members are patrolling the area, also looking for hostiles. One of the HECU members suddenly yells out that he sees another team approaching. In a jungle area, six HECU members are exiting a building, on a mission to check the area for any sign of hostiles. With the Black Ops, they are part of a 'dangerous and very efficient clean-up crew' sent to Black Mesa in case of emergency, and are supposed to work in concert with the Black Mesa Security Force in these cases. The Marines are often referred to as 'grunts' by fans of the game and also as such by Black Ops Operators in the game. Barnes and Sharpe, and train at bases guarded and staffed by members of the Military Police. Members of HECU are trained by drill instructors Dwight T. The Marines of the Hazardous Environment Combat Unit ( HECU) are specially trained to deal with a variety of indoor combat situations, particularly involving a dangerous environment and unconventional enemies.

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