Chromis can be somewhat difficult to diagnose so best not to jump to conclusions at this point. I would definately proceed with getting that QT
going as it may yet be needed. Even if not needed for this particluar instance, all future additions to the display tank should end up there first.
As far as the problem at hand, a fish passing is a definate concern buy could easily be from stress or improper acclimation. Since it has only been two days since introduced, I would surmise acclimation. As far as the bruises, this is where it can get difficult. The larger scales on the chromis can reflect light much more than your typical fish and give the appearance of discoloration when it's simpley a trick of the light.
The thing to watch for here especially if you do not have history on the clowns predating you, is the possibilities of Brooklynella, Vibrio and/or Uronema.
The main symptoms to watch for being: bloody lesions, excess body mucus, color loss, loss of appetite, surface gulping, heavy gilling, scales on end, red blotchy appearance, gaping mouth and general lethargy.
For now at least I would work on the QT
and perform those water changes I suggested earlier. Just be sure the change water is well aerated/heated a day in advance to allow the chemistry to normalize. Do a change every other day for 7-10 days and about 20-25%.