SCP-14208 and The Way the knife works

When Officer 924 Goes down the hall to SCP-14208 then his partner- Officer 452 hear's children screaming for 10 seconds. But officer 924 doesn't hear children at all then you will think nothing is in that room. When He enters that room to prove nothing is in that room except he sees nothing except a knife on the wall. When he grabbed the knife on the wall he saw 5 children with no one there. Immediately the door closed on Officer 924 and he knew right away that he was supposed to kill those children.

After that officer 452 heard the screaming again for 10 more seconds. He yells, "WHAT ARE YOU DOING!!" He heard no answer. Officer 924 had a sudden urge to kill himself… So he did…

The story of SCP-14208 is more known as a Mind-Controller to kill other people and him/her self. If the subject knows that person it will show itself as another person with another knife and warn that person to leave the area or death will come upon them. If that person does not leave the subject will kill them.
So in the end, almost everybody will die. SCP-14208's main goal is to kill everybody one by one until every person on the earth dies.