[BFritz]

saw 4 takes place at the same time as saw 3. when they get the tape during the autopsy, that takes place after the events in 3 and 4.

They don't take place at the same time, because you see the dad from 3 looking for his daughter, which takes place at the end of 3. Then, why would the killer in 4 have found that tape after he killed all those people in 4?

He found the tape in the autopsy after 3, but then I just thought about this: how was the dad from 3 still in the tunnel after the dude in four finds the tape and plans all that?