Swarmkeeper
Hero
Why would someone Ready a teleport (or teleport-like) spell to avoid damage? If they are not attacked, the spell slot is wasted.
Also, @Maxperson one can't move and attack as a Readied action. Read the rules on Ready again - there's specifically an 'or' in there.
Finally, enough with the "punishing the player" nonsense. I don't see anyone proposing the ruling as a "gotcha!". As long as the player is made aware of the stakes involved with their action, they can choose well enough what they want their PC to do. Remain in the blast radius? Take damage from the spell. Teleport beyond the blast radius? No damage from the spell. Want to rule this differently at your table? Sure, why not.
Also, @Maxperson one can't move and attack as a Readied action. Read the rules on Ready again - there's specifically an 'or' in there.
Finally, enough with the "punishing the player" nonsense. I don't see anyone proposing the ruling as a "gotcha!". As long as the player is made aware of the stakes involved with their action, they can choose well enough what they want their PC to do. Remain in the blast radius? Take damage from the spell. Teleport beyond the blast radius? No damage from the spell. Want to rule this differently at your table? Sure, why not.