I can't really see the issue here:
If you're sitting at 4 runes down, OB ready and <20 RP why not risk a quick glance at the swing timer?
If you're sitting at 6 runes down, half a second till OB is ready, 20-40 RP, KM why not risk a quick glance at the swing timer?
Sure you don't do that with fires spawning under you but there are plenty of situations where you just sit under the boss with nothing to do but watching your bars.