I have one, if I can be so daring.
A game that is at least somewhat similar in genre to Doom (action-oriented survival horror), we have the signature mechanic from F.E.A.R. Time slowing.
For the sake of working in DoomRL, it would best exist as either a unique item that you use which lasts for X amount of time (10 seconds? I don't know, it's just a number that can be adjusted); I don't think Kornel wants to dare add a new mod to the game, with the complications of needing to work it into assemblies. How it could work is simple:
In keeping with the theme of time slow down, it will not make your weapons fire any better, or make you move faster. Instead your reflexes would increase, which offers you but exactly one benefit, the ability to react. Thus, while it is active, you gain all standard benefits of dodging enemy fire (exempting arch-viles and revenants, due to the way their shots work). You can see it all coming from all directions, you're going to be just that good. In other words, you would have your dodge chance for everything, even while holding still, including Dodgemaster if you've got it. The absolute best time to use it is at the start of a floor when you're surrounded. No phase device? No problem. Pop this bad boy, and you'll be able to chain fire while dodging it all. The idea behind it is that it won't last very long at all, but when you need it, it's gonna rock.