It is written "weirdly". No, I read it as SN mixed in water, also. There's no way I'd trust any SN mixture that's been sitting around for even a moderate length of time. Entire issue becomes mute if it's only mixed when ready to use.
I'm kind of intrigued by this mini ice cube idea. Even if the mixture wont freeze on it's own because it's a salt mixture, there is still possibility of joining two "half" cubes together, with the SN placed in a small formed divot in one of the cubes. It wouldn't solve the vomiting issue, but it could solve the taste problem. Someone would have to do some experimentation to see if it could be done. Multiple mini cubes would be best, I believe, with the 25g divided up nearly equally amongst them. Still might be a melting issue, though. It's still an intriguing idea.