According to the app properties for the camera, its path is system/priv-app/Camera.apk. Whether this has changed or not since 4.4.2 I don't know, but this mod points to /system/app/Camera.apk, which makes it obvious why it doesn't work on 4.4.3, since it's replacing the wrong Camera.apk. The file is still present in /system/app, though, and the connection (or lack thereof) between the two is unknown to me.
When manually replacing the files and rebooting, the mod seems installed, since the flash is available in night mode. There are, however, other odd things going on. Photos taken are no longer showing up in the lower right corner in the camera app, indicating a shortcut to the image editing and gallery app. The counter ticks on when taking pictures, and the image files are visible in the file explorer - however not consistently so in the gallery.
I suppose we have to further investigate this.
EDIT: Derp. ckpv5 was a slice of a second faster.