I got the cleats on my shoes, got my left foot clipped in fine, right foot no problems. Pedal for awhile on the trainer. I unclipped the left without any troubles. I tried to unclip the right and I couldn't. After several tries I just left my shoe on the bike and jumped off. I tried with my hands to get it released and no joy.
Cleat might be over tight too. If the cleat is not flat (square) to the base of the shoe it will deform a little bit. Seems to be enough to cause this. I've run into it before when getting new shoes. Just need to adjust the cleat and tightness to figure it out.
Sounds like the cleat screws are overtightened... just take a screwdriver and loosen then 1/4-1/2 turn and you will very likely be able to unclip.
Keep in mind that Speedplay cleats needs to be lubed once in a while and cleaned out once in a while... I lube my cleats about every 2 weeks and clean then every other time (taking the metal plate off and cleaning with rubbing alcohol to get rid of gunk and old grease). Perfect function and very long cleat life.