Securing the seed phrase is one area that we have not arrived at a generally accepted means of storage because of the sensitive nature of the information being stored. The challenge is that every means of storage carries a significant disadvantage. For instance, writing it down in a piece of paper and locking it away have the disadvantage of the paper spoiling over time or when in contact with any liquid. Steel plate also has its burden of safe keeping and the possibility of corrosion.

The worst option is what is being described in the incidence which is carrying the seed phrase about. I have seen several recommendations in this thread but some of them are not straightforward and it will be very bad to use a method that will become problematic during retrieval.