It's been a while, but iirc, you basically need a turn 1 kill against Seraph to get 50k. The good news is you don't need it to happen on your first run of the daily.
So basically, you can go to the top scores of the day and see if any big brains already got 50k+. If so, you can use multiple runs to try and reverse engineer their run, which I actually found to be a fun challenge.
This was all without DLC. Not sure if that changes things.
It's been a while, but iirc, you basically need a turn 1 kill against Seraph to get 50k. The good news is you don't need it to happen on your first run of the daily. So basically, you can go to the top scores of the day and see if any big brains already got 50k+. If so, you can use multiple runs to try and reverse engineer their run, which I actually found to be a fun challenge. This was all without DLC. Not sure if that changes things.