If you succumb to cancer or another often fatal disease - "fail to resist" it -- that clearly has to mean death. If you succumb to a cold -- failing to resist i

If you succumb to cancer or another often fatal disease - "fail to resist" it -- that clearly has to mean death. If you succumb to a cold -- failing to resist it just means you are stuck in bed with a bad cold. So I think it's probably because you are used to hearing it used with more serious illnesses, and in your mind a seizure is closer to cancer than a cold.