> when she could prove that the outbreak in Wuhan was not any strain that the lab had a record of storing.
You answered your own question. That's the point here: the evidence does not point to a lab leak.
Even if we take this at face value, and the denials were fully truthful, this tells us that:
1) it didn't leak in that form from that specific lab (of the several operating at the Virology Institute), assuming they had good record keeping. But it might have leaked from a different lab, or it might have leaked from her lab and then mutated prior to being discovered. (And, while it might seem unlikely that it mutated without any trace of intermediate forms being found, that's the exact assumption the zoonotic theory already requires...)
2) Someone in a position to know believed that a leak was plausible based on her knowledge of the types of research being performed, the quantities of material they had on hand, the safety protocols they were following, etc.
I suppose I just find that less reassuring than you do. :)
I don't know, and I'm not asserting, that any of this is true. But given what is known about the types of research being done, this doesn't seem like something we can rule out either.
For one example, the article quotes Shi Zhengli, a lab director at the Wuhan Virology Institute, who had been doing research on RaTG13, and who upon realising COVID-19 was related to RaTG13 was immediately was concerned it had leaked from her lab. According to the article, she lost sleep over this, and was enormously relieved when she could prove that the outbreak in Wuhan was not any strain that the lab had a record of storing.
I find it surprising that you are so much more convinced than a lab director of the lab in question that no such leak was possible. To be sure, perhaps she was suffering from an excess of caution...but if she found the thought plausible enough that she lost sleep over it, perhaps we, vastly further away and with much less information, should not rule the risk out entirely?
In any case, if you feel comfortable, based on your knowledge, concluding that you can rule out the lab leak hypothesis, that's great, but it does seem to put you at odds with basically every expert I've seen quoted so far.