Remember that these statistics are specifically from Amazon warehouses, and not from Amazon warehouse workers calling from home. We'd need statistics on calls from workplaces. A quick google scholar search finds suicide rates [1] in the workplace which are significantly lower than what you cite as general suicide rates. I couldn't find any data on 911 calls, so we can't really draw any statistical information from this data.
[1] https://www.sciencedirect.com/science/article/pii/S074937971...