Putting it much more delicately: While I understand your frustration, OP- there are already solutions in game. There isn't anything about the countdown that forces people to run in when it hits zero. It tells you who started it and if you casually glance at the party list and notice that that person is not a tank, hold back. You can also type a quick warning in party chat if you feel some people may still run in. Like: "Don't run in unless a tank goes first or you'll eat floor." And if people still run in, there is virtually nothing that can be done to save those people, lol. Echoing KaitlanKela above, just kick the offender if they pull and move on. ^^
