Am I an idiot?

I was running dusk vigil yesterday and I had a tank die on me in the small amount of time it took me to draw a single card. Sometimes you just can't keep people alive. Partly it might be that recommended gear for tanks is iffy, part of it could be they're also just terrible. I've got a general rule that if you go from full hp/close to full hp to dead faster than cure/benefic can be cast, then thats on you. I'm already babysitting while we're in here, not my job to babysit your gear outside.