Can you fit an external "button" like the highway coaches have? We live in an MCI which has this button on the front (with a hole in the shaft for a padlock). Pushing it shoves the inside door opening handle past the lockover point, then you pull the door open.
Some of our other coach buses have either pull rods or buttons, too.
I tried to upload a video of me pressing it, but I guess it's not a valid file type...so imagine a palm pressing this.