Well, yes, the overpressure/tamping/chunky salsa rules are ignored this time around. But if you're going to actively seek out in this corner, there's no reason the GM can't say the spirit is obliterated anyway. For example, just because a gun does 3P damage, you don't get to point it at your forehead, pull the trigger, and go "LOL I only take 3 damage".
Definitely a "GM decides what happens" kind of scenario, here. With regards to the mitigating/dampening effect of the earth spirit smothering a grenade before it goes off... Reduce the DV by the Force of the sacrificed spirit? I'd probably go for such an answer if I were running a game where a Player wanted to try this.