so in the normal stage, he kinda jus sits backstage or hides in the supply closet, unless you end up seeing the 'EXE' parts of him, which may easily happen when flipping through cameras. Then, he will start to corrupt each camera and slowly get to the office, where his right hand can turn into a g*n sorta thing, a knife, or any bladed weapons/stabby stuff really.
might add more to it. so i had this idea about like a police night where they come and investigate and scratch.exe turns to his 2nd form and you play as police (2nd form is hidden behind the black block thingy)