Sorc: Bubble > Dark Infusion (3.7 seconds and an average of 15k healing)
Op: Kolto Injection > Surgical Probe (3.2 seconds and an average of 11k healing)
Merc: Rapid Scan > Healing Scan (3.2 seconds and an average of 15k healing); optional Emergency Scan for 6k more
Two coordinated healers can easily drop 30k on a target in about 3 seconds assuming average crits. More if their cooldowns are up, and more still if they're single-target healers (merc ftw).
The numbers you posted with the different healers are healing that in the span of 2 GCDs. So if you cut that in half for 1 GCD, they're healing an average of about 13-15k HP. If you look at the OP's combat log, you'll see he does the Sweeping Slash twice in the span of one GCD that adds to the total of the 31k damage he took in that time frame. I don't know of a single healer that can do an average of 12k HPS single target much less two. While I agree with your numbers, those are over a longer time period. We've been having our assassin tank get hit for over 25k consistently in the span of 1.5 seconds; too much damage for any set of healers to deal with in 8 man ops.