Originally Posted by
Cincierta
Everyone else's hp is mitigation, don'cha know? /s
In all seriousness, most likely they had chat turned off, and probably wouldn't have noticed unless someone was spamming notifications/sound effects in chat. I probably would've told the party to hold back on following said tank until they turned it on. And since they weren't rolling on loot, you can always wait out the loot timer if you hold back so you can kick.
I hate to be the one that says it, but if you have the menu to kick up before a boss dies, and you're fast enough, you can votekick him before new loot gets added to the table.