Silence is the Loudest Parting Word

"His other arm twitched with anticipation, ready to deliver that final blow, but it wouldn't make that final movement that would drive into the man's flesh and crush and break and kill- it wouldn't move. He couldn't get it to move. He didn't want it to move." Post TWS. How the Winter Soldier grew from being 'Hydra's fist' to something more.