Playing as an engineer this is basically impossible – as the OP says the champion summons krait which either kill you, or you kill them then they explode, killing you. Those krait should not be in a mission or event where you can’t dodge, there’s no fun at all in dying with no chance to avoid it. In theory you can interrupt the summons but the engineer doesn’t have enough interrupts so even if you catch the first one or two the champion summons again during your cooldown. Once you die all your allies are killed at which point there is no point in attempting to restart, leading to a long tedious ten minute ‘walk very slowly along the planks’ section. The pacing is terrible and then you get to a fight which appears impossible to win unless you picked the right class. I’m off to play something else and hope this gets fixed soon.