Couldn't get attachment to work, so stuck the image on my server.

This was in an RvR zone, I'm only level 33 but had the boost. Does the boost not affect amt of disrupts, etc.? I know in PVE that a level or two makes a huge difference on # of disrupts and damage mitigated.
I was going to just remove the person's name since it shouldn't matter, but I guess not all lines are equal length so a bit too much effort. They are lvl 40 and renown level 60 and a Chosen, so, yes, someone that plays a lot and probably has great gear. There was some black orc there that ran off that was level 40 and renown 52, & he mitigated what I'd expect w/ some huge gear difference (some 65-75%).
The history goes back more & I was doing a few more spells earlier, but gradually lost interest after a couple minutes. There was no barrier pots or anything like this being used (the 1 damage from melee attack comes through). The only spell that did any damage was the Rune of Cleaving, which was mitigated only 97.7%, rest were at 100%. Melee was mitigated 99.54%.
Can someone explain the factors at work here, in regard to the near 100% mitigation and how a lower damage spell that uses the same damage type (elemental) achieves the 2.3% damage, vs 0% for the others (presumably ruling out toughness).
thanks