Just SSS things.
For those who didn't play Arknights, SSS is a special type of gamemode where instead of retreating characters, you can 'pile on' characters atop of each other, and the next character will inherit bonus(es) depending on the type of previous character. In this picture, Gnosis inherited stats of 5 previous Sniper operators, which gives him +200 attack speed buff. For Mudrock, she inherited *3 Vanguard and 1 Defender operators, which grants her SP recovery per second, enabling her to spam her second skill and grants her +1 block.

Same as Irene, with Vanguard operators she can spam her skills per attack. It is a good way to clear even higher level enemies.

You need some good rng on your side to get the correct operators for the stacks of special effects you want and sometimes it doesnt happen you have to restart a few times, though thankfully you only need to restart the very level you are in (out of 8).

The rng can get pretty bad sometimes and once again you only need to complete the mode every two weeks.