Okay, there's a character who is force-fed multiple grenades. The resulting explosion does severe damage to their body, but doesn't completely destroy them, and their healing factor fixes all of the damage. Their chest is split open by the combined explosive force. 40 live grenades are inserted into their digestive tract, all throughout. Their size and shape is similar to that of a human. The question is, how durable would they have to be in order to not be completely reduced to a bloody splatter? Let's work with grenades with a blast radius of 9.14 m each.