Nah, you're misunderstanding how the shield works, the shield doesn't reflect anything. Accelerator would reflect the force of the blow back into the shield and the shield would just absorb it. The movie did something weird with it.
And if it did, Accelerator would just reflect the force again, presuming creating a loop until one of them moves off.
I also don't really get the point of all these ways of beating Accel from other universes. Toaru isn't a very high tier verse, there's plenty of verses or characters from other verses that can take Accel. It's more interesting to try to find a way to do it within his own verse.
Hell I don't even get the obsession with finding a way to beat him. There's tons of people in his
own verse that can take out Accelerator. Why not focusing on Fiamma for once? Or Kakine? That guy is a freaking cockroach when it comes to surviving.
http://i.imgur.com/1AhleSW.jpg
Plenty of people above Accel to focus on.