Just to be fair, the X2 Taser is listed at 454 grams which is slightly more than 16 ounces. It is a double shot TASER and is the model most commonly carried by police officers. The X26 is a single shot TASER aimed as a home defense weapon.
A fully loaded Glock 17 weighs in at 32.28 oz which I believe is the lightest firearm typically carried by patrol officers.
Assuming she didn't have her eyes shut and was actually looking where she was shooting, you would have thought the fact the thing in her hand wasn't day glow yellow would have been a hint she hadn't grabbed the right thing.