In the opening scenes, the DX4 "vaporizes" the gunmen. However, the wall showing bullet holes would have been obliterated by the weapon, it is still clearly intact.
The syringe that was used for the murder was speckled by laser printing toner powder, while in the imagery it was used to inject ink to an inkjet cartridge. The toner powder can't and won't be injected - there are filling holes with stoppers in the laser cartridges, and the toner is added by shaking through a funnel. Cross-contamination between the two different kinds of printing color would render the cartridges, as well as the inkjet head and laser drum unusable.
When Trip is talking to Horatio early on, there is a large blood spot on his left shoulder.