I have a question, why does the clearlag remove all entities?  Because I was super proud to have found on skaro a dalek Pink fluffy that I brought in my tardis and I saw it disappear in front of me

Lag Clear is setup to clear most hostile mobs, and all daleks have the same ID, including the PFD. So when Lag Clear goes to clear anything with that ID, it clears the PFDs as well.

I was well disappointed when I managed to trap a Pink Fluffy Dalek in my TARDIS but K9 killed it. I guess it's a similar situation to the ID thing.