Question Ascension red phones don't ring when conditions are met

[Baofu]

So I was doing an easter egg hunt in BO1 Ascension and thought I'd try getting the red phones to ring on solo supposedly by killing 10 zombies, getting a Ray Gun from the box, and getting a Fire Sale power up. Well I did all three of those things and went to each phone and none of them rang. I got the one for the Fire Sale to ring only once but haven't been able to make it ring since on future runs. Is there something else that hasn't been mentioned on any guide or source to be found? Could anyone look at the script files and decipher if anything else needs to happen for the red phones to start ringing? Because I'm noticing a lot of incomplete information as of late and it might be time for an updated guide for everything.