There's a very obvious look on The Doctor's face when he hears that voice saying that - a face that reads something along the lines of; humans having to dance with half the species of the universe.

In other words, colored Ten not surprised nor impressed.

"And then what?"

However, Ten is also looking to see if Jack recognizes this face - all things considered, Rose is from his future.

As far as Jack dying and coming back; usually that isn't something The Doctor would fret about; however considering the rules have changed - he sort of is.