how tough is the VSR fight?

[Diogene]

One day I got a tell on my chanter asking if I wanted to help killing VSR for a random druid. I had never done this one before with a single group. Dude told me it was cake as long as we chanters kept on the rune chain. Finally our comp was as follow (all 60) druid, mage, cleric, sk and 2 chanters. We were low on dps so we both charmed a pet. Once sk had aggro we were supposed to chain rune. Thats what we did but we wiped in less than 2 minutes. that 1k lifetap is really sucky. Iirc group was bitching about sk not preventing VSR to lifetap, there was a trick to make him run around, by always moving. In this sense, I guess lifetap isnt a proc but a spell. Still unsure about this