One time on this level, and one time on E1M1, and some times not so fatal on many other. I just used to grab items with F button (my use key), and shoot as shoot only (other than dialogue with friends in some games, yes doom 3 have control displays, and i have bit of annoying from it too)
Hmm I already tried use crates as shields and throw, and throw damage looks cool for me(still not tested for now, just thoughts)
I know about movers difficulty, i implements this in some my dead projects, but many years ago, when i first time make my first levels for game with valve hammer editor entity parenting feels like largest problem, and my naive game-physics meaning drawing me utopic pictutes what great things i can do with this.
And with access to retribution mod, i tried to make tranin, but other entities rotates around itself origin instead of global train center. (marked with special texture)
And even more shocking later i know how rotating elevator made in original game... (Just hidden button and fake visuals as part of original train entity)