Myron activated one spell (technically two runes, gravity & erosion), it was prepped before the post he used it in. (during the timeframe in which he created his mask, which began on post 6.) It's a disintegration ray, and it's pretty much his only spell that moves at bullet-like speeds. The ray was shot at point blank, after Myron began tracking his foe's underground trajectory. Corban used a railgun spell (?) to shoot both his sword sheath and sword at Myron's solarplex, half a second after the sheath struck Myron's mask-shield, he fired the laser. ( The laserbeam is coming out of the mask's eye.)

Defending against the laser beam, Corban would react the second he hears the sheath clash. He creates a graphene aerogel around his sword, enchants it to be stronger than any worldly aerogel known to date, and then erects a magical sublimating conjunction around the sword's blade capable of dividing the beam off course. My issue with this is the split-second decision it would take, the difficulty needed to channel and activate a complex spell and a barrier at the same time, and the fact that aerogel wouldn't actually be able to handle heat or kinetic pressure of this caliber; I had to research graphene aerogels to be sure, myself.

I don't mean to entirely speak on behalf of Divinity, so of course, his rebuttal will also be important to hear.