How does the Zoltan Explosion work?

In both the Advanced Edition and up-to-date Standard Editions of FTL, the Zoltan race explodes on death, dealing damage to hostile targets in the same room they are in when they die but not hull or subsystems. This much I know, however, much remains to be known about the Zoltan Explosion, or should I say Zplosion!!

The Zplosion has been thought to deal 15 damage to the attacker, so I'll use that for a base number but I haven't had it verified that it deals exactly 15 damage.

• How much damage does the Zplosion do?
• Does the damage vary from a target in melee vs. a target in ranged combat (still in the same room though)?
• Does the Zplosion's damage increase if the Zoltan has combat experience rank 1 or 2?
• Does the Zplosion's damage vary against targets with different hit point totals? That is, does it deal 15% of max hp, of 15 points flat? This could be tested on other Zoltans or Rocks or Crystals.
• If a Zoltan is mind controlled and dies under this effect, who does the Zplosion harm? The original owner's team? The hostile influencer's team? Both?
• If a Zoltan Zplodes in a forest and no one is there to see it, does it deal damage to the trees? (Okay, this last one is a little silly. You don't really need to answer it.)