My civilian injuries are far less serious than yours. My left ankle won't rotate enough to consistently get out.

I've pretty decided, just do platforms.I'm 65, not going to be racing, not going to be seriously hill climbing. Why do I need clipless pedals?

You already have injuries. Why risk making those injuries worse by putting yourself in a situation where if you can't get out of the pedal you open yourself to more injury?

OK - benefit of my recent research.

just about every clipless pedal on the market takes 15 degrees rotation to get out.

As near as I can determine the two exceptions are Shimano SPD model that is adjustable as to release, and possibly Speed Play zereos - but I have my doubts about the Zeros, and don't actually own nor have I used them.

SpeedPlay Zero _may_ be adjustable to a lower degree - but the two times that I talked to Speedplay tech support it was like I was talking apples and he was talking oranges.After I repeatedly asked the tech "once you set the float to zero" do you still have to rotate your foot fifteen degrees to unclip" his response -That is not the question you shouldd ask" said the tech. Well, hell - it's the one I wanted answered - he never answered it, at least in any way I could understand.

Note This is not approved, speedplay says it can't be done and I am not suggesting you do this - although, I understand several people are doing so successfully.

Speedplay Light Action pedals - with Zero cleats. Definitely not recommended or approved by speedplay.

I researched this somewhat after going down in the grass several times due to being unable to get my bad leg out.

I suggest you focus your research on Shimano SPD's that have adjustable release or speedplay light action with Zero Cleats.

As near as I can tell, all the rest of them require a 15 degree rotation, or more to unclip.

ETA

To be clear - increased swivel = float. Speedplay has the most float and the Zero cleats have the most adjustability on the market to the best of my knowledge.
Note: float has to be overcome to unclip. if you are swiveled in 15 degrees on float , you are going to have to rotate your foot another fifteen degrees to unclip - meaning you will have to rotate total of 30 degrees to unclip.

The Zero cleats have the most adjustments possible available on a standard order pedal.