Remember that the tank can click it off.

In dungeons the healer will not get threat until he or she heals the tank so by clicking it off the tank has time to generate threat.

In trials, the tank will open with fight or flight or unchained and is usually just one boss so threat is easy to hold.

Yeah, medica II before pulls is dumb, but even if they don't listen, it doesn't really make a difference anyway.