How big is a Model 3 battery pack again?
[1] https://en.wikipedia.org/wiki/Toyota_Mirai#/media/File:Toyot...
You can of course fearmonger on any topic: in any gasoline car on the market today, your back seat passengers are sitting on a huge quantity of highly flammable liquid! And it is stored in just a regular plastic container!
In fact, the Mirai only has 600 MJ of energy stored in its fuel tank, while a gasoline car has around 2200 MJ! And a gasoline leak will pool around the car, while a hydrogen leak will go safely away up into the air due to buoyancy!
Yet nobody bats an eye at the gasoline car. We engineer our cars such that fuel tank rupture is extremely unlikely in even severe accidents, with redundant safety systems all around.
Unfortunately a lot of the battery capacity gains of the last 15 years have resulted from loosening these tolerances for fire/explosion, I'm thinking about lithium-ion and lithium-polymer chemistry here. Lithium-iron-phosphate is an example of a safer chemistry, but it also has significantly lower energy density, it's probably still better than NiMH but not anywhere near as much as lithium-ion or polymer types.
That means that if you are looking at an iso-safety sense, the gains have been much slower than "maximum potential even if you are ok with batteries exploding when overcharged/overloaded/punctured". We have just been ramping up our tolerance for batteries of the latter type.