That is odd. A too-low reading would result in less insulin and a high blood glucose, which can be extremely uncomfortable but is not immediately deadly.

If it had read too high, it could result in an insulin overdose, which can indeed bring coma followed by death in fairly short order.

Theoretical you can get a hyperglycemic coma but for that to happen you need continued and sustained high blood sugar in the way your toilet would smell like a sugar factory for quite a while.