Does the Black Box heal multiple times if it hits multiple people?

Does the Soldier's Black Box heal multiple times for +15 a piece if it hits multiple people, or is it only +15 if it hits anybody at all?

Can this effect crit? (can any healing crit in TF2 or have I played WoW too long...)

Solution 1:

Yes, you heal more if you hit multiple people. I just tested this. However the GUI displays the +15 over each other.

If you want to try it yourself, I can recommand using tr_walkway. Just set constant resupply off and bot movement speed to zero.

Solution 2:

Yes. The more people caught in the splash damage, the better.

The healing effect can't crit, but will heal the full amount even if you barely deal damage to them.