Thank you all. Yes, with toggles off, the Tanker still prevents explosions (unless I do it like Nayeh said, extra thanks for that). For the other archetypes, with all toggles off (I'd already tested with all damaging toggles off), they do explode but they do the constipated crouch thing 4+ times before blowing up instead of 2+ but that's likely observer error.
I'm sorry for the bad report. MODS = You may delete this thread. It was user error. Apologies.
Again, thanks for the replies.