[SR] Barrier spells V. Grenades

OK, I know how grenades are treated as far as barriers go (using the
blasting through barriers table) and I know how the barrier spells
treat them (as per spell description), but how does one resolve the
effects of a grenade against a barrier spell exactly? I guess what
I am asking is if the spell is broken if the grenade blasts a hole in
it and how does one calculate the chunky-salsa-effect if one were,
say, trapped in a hemispherical barrier spell with a live grenade?

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ISLAM: Winning the hearts and minds of the world, one bomb at a time.