Compared to her normal targets, Iri's sword is large, heavy, moving, and mostly concealed. Iri certainly wouldn't politely hold it still for the two seconds it takes to put significant energy into it.
The lack of a connection between them being at crossed swords to the sudden flick of the wrist cutting a car with iri on top of it seems awkward.
Interesting close-up, though the pattern applied to the hair needs to be tweaked in the future; it only accounts for root to tip, and ignores any ends prior, eg. the 'spikes' of hair where some ends and flares off from the main mass. You can see strands crossing the space, rather than flowing into it properly. /nitpicky
I think the best/easiest way to 'be careful' about it for the future while retaining speed and ease of drawing would be to draw the lines for the hair pattern going from the tips of the hair (bottom as well as the 'jags') to the root, instead of vice versa.
Smaller would actually be -worse- as the majority of the issue with glass-related wounds are the small slivers which are nearly invisible beneath the blood in the wound. Large shards lack the penetrative power to seriously injure (No matter what various shows/movies/games show you with standing shards of glass cutting -right through someone-, it just doesn't work that way) and are very easily detected and removed. Powdered glass, on the other hand, provides not just a surface irritant of unbelievable proportions but also provides another, deadlier hazard- inhalation of tiny glass particles that would rip your lungs apart with each breath, until your lungs filled up with blood and you drowned on solid ground, each tortured gasp sending yet another dagger of pain through your chest, like the worst bronchial infection ever times a thousand. Not pleasant.