The long-term solution to this is weeding out the dudebro gene that somehow has crept into FFXIV (at least the North American servers, anyway). The immediate solution is letting the Neanderthals learn for themselves that healers have limits and that they're not miracle workers. Contrary to what some people believe, there's no Time Attack mode in any of these dungeons. I'm sure Yoshi-P would notify us if that were the case and I'd steer clear of it, given the cancerous attitude of speedrunners in ANY game.