Defeat Mimiron without anyone in the raid being hit by the following in 10-player mode: A Proximity Mine, A Rocket Strike, A Bomb Bot.
It's not particularly easy for everyone to avoid all of these, but it is fairly easy in nature. The A Proximity Mines spawn throughout phases 1 and 4. There are always gaps within the mines, making them easy to avoid. The A Rocket Strike from phases 2 and 4 are a bit harder to dodge. They do an immense amount of damage and nothing in its path will survive. Bomb Bots are probably the easiest to avoid. It helps to have a hunter place a frost trap near the center to slow them down. Have range kill the bomb bots before they reach the raid and you'll have no problems.