First, they individually tested the counter-rotating proton beams, they didn't actually collide them.

Second, even after they start colliding, not all experiments will be done at max power, they'll probably gain experience by slowly ramping up the energies and taking care of a lot of routine experiments while they gain experience for the big collision.

Even the big colliding experiments will not necessarily create devastating effects, it may not be until the 10th or the 100th or the 1000th try...and as you point out, even the worst need not happen immediately.

So you see, we can afford to be paranoid for years!

But I look at it this way, if Homo Sapiens has to collectively cash in, I'd rather it was something noble like this than with some pointless debacle like nuclear war or runaway global warming, or some random cosmic event we were too stupid or too slow to avoid.

And perhaps in some distant future, an alien intelligence will conduct a survey of this little solar system, reconstruct what actually happened, and erect a monument on our still-orbiting moon saying something like "They went out in style, and with class: asking questions all the way out."