There are perhaps 2 things to keep in mind.

Firstly, all talk in game about the Lalafell escaping to a different shard is phrased as speculative, as there is currently no way to prove that hypothesis. Even when Y'shtola looks at the big gate she can only presume it leads to another shard. It wouldn't be the first red herring we've had.

Secondly, shards are alligned not just by element, but by polarity. That's how the First and Thirteenth can be aspected to light and dark, or passive and active. As such there would still be another lightning aspected shard that the Lalafell could go to.