I can't imagine getting a horse in that far and not getting it loaded. I had the same thing happen to me and 4 hours later this is what I did. Alot of people can't figure out when to give pressure and when to release so I had someone in the trailer with a long lead and loose. If the horse wanted to come back out I let it and then when I lost my temper I took my buggy whip and kept snapping it at the horses rear legs and not once touch the horse. It bounced around a bit and I kept at it and it went in and was fine. I do believe your tack comes oout and folds up and you can open both sides.
The next time I loaded by myself with a lunge line up through the front so I could lead the horse forward but be behind her with the whip. Took 5 minutes to load.
After that fiasco I now stand in the trailer off to the side point the horse in and take my buggy whip and gentle tap her behind and she goes in with in 30 seconds but at anytime she gets her front end I am ok with her for a bit and if she backs out I let her and then I mean business and she goes in.