Swamp Walker and drop rates.

Hello, i've been stuck on swamp walker for a while now on normal, i Was playing enzo with thunder cage and dps wise it shows i'm atleast 30k up. Dying isnt a problem i just can't get him down that 1/3 hp at the end of the timer. I switched to bunny since she was a good electric option but she was lvl 10 so i wanted to lvl her. I opted to get her red mod electric condense, but i've leveled her to lvl 40 in doing so and still haven't gotten it, at this point my runs are 2 minutes max. I am kinda stuck because i can't build more mods on her without capacity increase. I need help.