to be increasingly fair the regenerations of ten and eleven were both extremely violent. tens destroying the TARDIS and elevens practically leveling trenzalore, so it would make sense if the energy hurt enemy mobsWhilst I think the scene in question was quite stupid, I think that making the particles do some damage is a good idea. After all, the Doctor does warn people to 'stay back' whenever regeneration energy starts appearing. I'll see what I can do.