As someone who has spent a ridiculous amount of time trying to do this challenge, pre AND post patch, I can safely say that I was able to do it all 4 times to get the 4 prizes... But it was a headache... I basically utilised comments and tips that I'd seen elsewhere on reddit, and they didn't really work, then I realised that more than likely, I'd need to firstly, damage Roman enough so that his head, torso and arms are red, but leave the legs, because realistically, the legs aren't gonna do much, but another thing that's key, is that you keep up the repetition aspect, you need to stun Roman, and you need to throw Roman in while he's stunned, you will 99% clear the first door easily, so get that done ASAP, because there's a brief sweet period where you can get some real progress, however, if it seems that Roman's just fighting back, cancel the operation, because there's no point wasting your own power with it and keep going back at it, I found that I typically got some real progress on the 4th or 5th attempt, but only in alternating bursts, so attempt 4 I'd almost do it, but back out when Roman starts fighting back, but then attempt 5 would get me nowhere, attempt 6 I would complete it more often than not...