freddy cannot kill you if the camera is on her (this also includes when the cams are down) so as long as the cam is on her she cannot enter your office even when the door is open
freddy will also ALWAYS do 5 laughs before she reaches the right door so you can actually just count till 5 and know exactly where she is at without ever needing to look
if she's at the right door cam each laugh she will go back and forth if you plan to check any cams while she is at the right door cam always close the door first then look at other cams