This diagram is way way way too conservative with the “see you on the other side” classification. To name a few: fluorine will literally make you catch fire instantly (if there’s more of it, you will basically get burned to a crisp before you can even blink), caesium will violently react with water in your mouth and produce so much hydrogen and heat, the whole mixture will instantly explode (in fact, this will not only be a usual, fire-like explosion, it will in addition to that be a so-called Coulomb explosion, which makes the situation even worse)