Jack is just about to speak upon answering the call when the Doctor talks all over, not that that's anything unusual.
"Now breeeathe, Doc. I'm in the Plass, and it's..." He takes a look over to where Rose is with the... other Doctor? Hand-Doctor? He's not sure what to call him. "This is sort of a case where I don't know if you need me to break it to you first or let you just see with your own eyes. But trust me, you aren't crossing your own timeline on it, so you can take that concern out."
After a moment's thought, he adds, "And all the other genuine signs of a temporal control problem didn't get your attention?"