Alright. I can see multiple scenarios unfolding, but in the end it will be up to Innue.

If it's rationalized that Corban couldn't summon the second barrier (aerogel + disjunction) in time, then I can see the annihilation beam eating through his diamond barrier and dealing severe damage. This is the worst case scenario for you. Although the gems are resistant to fire and lightning, it's not mentioned that they're upright immune, so it's wholly possible for a peak level energy blast to get the job done.

If Corban's second barrier is created in time but not fast enough to gain its full strength, then I can see the late sparks and stray blasts of the laser leaving vicious burns at most. Perhaps an explosion as well that would send Corban flying.

If he upped both defenses in time, but they weren't strong enough to take the blast - again - horrible burns is my weather forecast. 

If he upped both defences and they were strong enough to deflect the blast... that means Innue thinks your character could react perfectly in the 1/2 second given.

There are probably other outcomes I'm missing, but this is what I see based on my understanding of my own ability.

On another note, how capable is Corban at self-healing?