It kind of is. You probably wouldn't die immediately (IE: In a split second). Depending on where you are, you would either die in a matter of seconds, minutes, or hours. If you were right in the middle of a ray (On the equator, right in the center of spherical focus), you would most likely die in a few seconds. Anywhere else is a debatable theory, depending on the sheer amount of subatomic particles.
When you're hit by most lethal forms of radiation, they're lethal because of the following: Radiation isn't actually made up of some unseen force, it's made up of supercharged particles ripping forth from certain matter. When such particles come off like that, it's called radiation. Now imagine about 40 dudes with fully automatic machine guns, with huge clips. Imagine all of them shooting, all at once, at one person. That is what radiation is like, except on a way smaller scale.
A small dose of radiation itself isn't going to kill very many cells, but if you think back to the metaphor about the firing squad, it adds up.