Applejack and the other ponies saw the aliens and heard the alarms in the break room.
The music stopped and the ponies were screaming while evacuating.
While they were doing that Applejack yelled out, "APPLEBLOOM!!"
Applejack ran out of the break room and that was when an alien grunt appeared, picked up and threw Applejack across the hallway with its claws.
Applejack rose up, and with her head down ran towards the alien grunt and headbutts the creature knocking it to the floor.
After she knocked the creature to the floor, she shot it before it could get up saying, "Now that's more like it!"
Applejack got more snacks and soda while the alarms were still sounding.
After she did that a headcrab appeared and Applejack destroyed it with her hoof.
She emptied the machines by taking the snacks and soda out, she puts them in her backpack, and heads for the surface.