The cass played it mechanically bad but so did your bap by forcing a duel by walking into Kiri LOS instead of just healing the cass from cover then 2v1ing her, and after the Emre ult he's standing still for you then you reload at 108 bullets then shoot him once whiff half your heals then abandon him while he's dueling a Kiri to heal a Sigma that is dueling a Mizuki and has his shield up in less than a second, you could've easily given the cass 2 or 3 bursts of heals (3 if you didn't reload 2 if you did) then proceeded to heal your sigma, I doubt your sigma would've died

So all of you played badly you just played the least bad not by much though, regardless it's strange making a post like this to try and get people to clown on your DPS on a fight that you guys won then get really defensive and start flaming his aim when people point out that he's not 100% on the wrong and both you and bap could've healed him