Olster,
Obviously I wasnt there in LAX with you and I have no idea whether your cabin was ready when they gave you the go ahead or what the "incident" was all about.
What i know is if your cabin brings up a cabin problem after line up is received (obviously telling you briefly what the problem is),one can find out if the delay may cause a problem to ATC.
I am pretty sure that all aircraft have by law 90 seconds on the take off point before being on their way.
But standing there for 3 minutes by just stating the cabin is not ready and not exiting the active runway will cause problems to all around you...
Just a thought...