More what I meant was Demo Shout and Last Stand, potentially stacking defensives during these times where you might spike, and using externals/alternate forms of DR. When you're this high up in keys, sometimes you need to get creative in how you live.
For example on the first end, while we normally send Demo Shout on CD for the rage, damage, and just overall more reduction over time, if you need to hold it to survive, it can be useful. Demo Shout, if it was delayed for a few seconds, would have been up to also help mitigate the spike from Proxy Strike, making it much less dangerous overall. It would have caught more hard light baton hits, as well. For Last Stand, you could have used it immediately after getting hit with Proxy Strike to instantly give yourself a bit of a heal, giving your healer more time to actually finish off a cast on you to get your HP back up.
For externals, this is something to keep in mind, as I assume you're in a coordinated group pushing this high, since you're running with a Ret Palading. They can always Sac you immediate after a major hit to also help give the healer time to heal you up a bit; if they're willing to pop bubble/a harder defensive/aren't in danger enough otherwise, they can also even help mitigate the major hits as well. If you had some kind of attack slow, as well, that could have been an option. It's important to leverage the whole group's tools at these high key levels, since otherwise you can get spiked like this, which is particularly dangerous since Resto Shaman only has instant cast heals tied to cooldowns.
Most notably, though, is that you should ask your Resto Shaman to purge the Hard Light Baton buff; I double checked before sending this, but it is the ability I remembered being able to be purged in that area, so you can just comfortably focus your efforts around just the early portions of hard light button times while the buffs get purged.