Rule 19.1.5. If the injured player had caught the disc, and the player has dropped the disc due to the injury, that player retains possession of the disc.
Does this rule mean that if I lay out, catch the disc, but knock the wind out of my chest so I drop the disc that I still get the disc? Or i'm running catch the disc, twist my ankle while slowing down and drop the disc when I fall ... I still get the disc?
In my opinion, this should be a turnover unless an INJURY time out is called?
That rule only applies if an injury time out has been called. An injury does not itself make that rule apply, only an injury CALL does. Where it says 'the' injury instead of 'an' injury, it is intended to refer to the injury that has been called under 19.1.1.
Note also 19.1.6, where an injury called as soon as the player is able to call it is considered to have been called when the injury happened. This means that I might have dropped the disc before an injury CALL, but could still get it back as the call is effectively backdated to when the injury occurred.