I never fully understood Mimiron's Head's ability. I thought it read something like "If you have 4 other mechs," not "if you have 3 mechs." This means all you need is two other mechs. And, as the video shows, it ignores stuff like Freeze mage's big board clear combo with Doomsayer + Frost Nova. Of course, it will destroy ALL of your mechs, so flooding for a higher chance to proc is just that and nothing more.