Bonus boss in cademimu is really annoying, especially for tank, especially for a not overgeared one. I usually just get comms, and leave it there.
If you're an undergeared tank there you can use some tools to ease your healer's job.
Shadow - Force speed
Vanguard - Hold the line
Guardian - ask the healer (and rdps*) to stand behind the rails at the edge of the elevator, this way he won't get sucked in, and you can guardian leap to them.
*rdps shouldn't really move around cause they can go down with the elevator in some cases.
'slingers with thei cover mechanic are usually going down, but this is a good source of some chuckle