SCP Agent ????? obtains the keys from the local authorities to begin testing. Tests show that SCP-004-2 through SCP-004-13 all fit into a single lock on the large barred door. 12 Class D personnel are assigned to test the effects of the door. Of the twelve test subjects each trying a different key to enter the room, only two survive. Opening the door with any key except SCP-004-7 or SCP-004-12 caused the test subjects to be torn apart in multiple directions; however, no dismembered parts were found until later. At the time of writing, only two parts of each subject have been recovered (with the exception of the subject using SCP-004-?, whose pieces were scattered in close proximity). The others have, for all intents and purposes, vanished from existence.
Of the two surviving subjects, only one (having used SCP-004-7) returned unharmed. The other came back in a near-catatonic state, able only to remove himself from the room and then collapse on the floor, and had to be restrained to prevent him from gouging out his eyes (see Appendix A: Mental Health Effects of SCP-004). The subject using SCP-004-7 said that he had entered a large room, impossibly big for the size of the attached building. After his exit, SCP-004-1 was propped open and an armed squad of Level 3 personnel entered. The size of the room is impossible to measure and the door frame and the individuals in the room are the only part of the room that can be felt or illuminated.