Salvation is an activity, in which you must rescue souls that are descending and ascending to oblivion. While you can instantly save the descending ones, you must hit the ascending ones with a Blast to free them so you can grab them. This activity is like so many of the others, in that, there’s a gold, silver and bronze finish to them.
To get a good score and the gold medal, you will need to increase your multiplier, which is done by saving the ascending souls. The multiplier maxes out at x4, but collecting both souls will still add to your score. Note that the multiplier will stay active as long as you keep in the air, as landing on any surface will end the multiplier.