Feasibility of modeless usage?

[bard]

I think of avy's default interaction as "modal" in the vi sense:

1. press a key combination (associated to e.g. avy-goto-word-1)
2. release key combination
3. a different input mode is entered
4. press a modifier-less key (e.g. e)
5. some processing is done (words beginning with e are highlighted)
6. press another modifier-less key (e.g. a)
7. some more processing is done (e.g. cursor moves to "e.g.")
8. editor returns to the previous input mode

I looked at the unused AltGr key on my keyboard and wondered, would an Emacs-style modeless interaction be possible?

1. press a modifier key
2. don't release it
3. press e
4. words beginning with e are highlighted
5. press a
6. cursor moves to "e.g."
7. release modifier

My hunch is no, because Emacs will wait for a key sequence to be complete before doing any processing; unless we "fake" it by creating key bindings for all possible combinations in advance. But maybe I'm wrong?