What's the right thing to do in these dungeon situations?

[Reinha]

i think "ok so maybe this healer might not like this pace, but they certainly aren't calling out the rdm" so I just assume everyone's ok and continue. The healer never really had to heal me anyway

However, if I had a guy like the one above in my group again doing what he did, and the new person was too self-conscious to speak up

Why do you assume the healer had any problem with it? I'd hate it if players just assumed I was incompetent and mute. Do your job and press W more often.