TMMYJMMY

I'm in the middle of putting my engine bay back together after painting it and I just put the ac/heater box in and i put the three screws from the inside in already, but i have this stud with a 4mm head on in it and I don't know where it went. I'm positive that I goes on the inside under the dash in on the passenger side, there are only 2 hole that are visibly. Let me know if you know where it goes and here are some pictures to help. Thanks!