I think I know how Ruby wound up in just a shirt. That is, I think I know the reason he was presented that way.
Realize that it is a staged picture. They wanted him in just a shirt because, first, it makes him stand out. Everybody else is in a dark jacket. So, if he too was in a dark jacket, then he wouldn't stand out- and they wanted him to stand out. But, in addition to that, the shirt alone is better at making him look disheveled from the fight. Of course, it wasn't really a fight. There isn't the slightest indication that the shooter was putting up any resistance or acting aggressively or hostilely towards the police. And, the very idea that a man as short as the shorter was could resist and oppose the bevy of big men who were swarming upon him is ridiculous. Why didn't it just end in the garage? Why wasn't he subdued right there? How could he possibly get out of those predicaments that we saw him in in which he was completely overwhelmed? How could it possibly drag on into the jail office? But, that's the story, that it did, and they wanted to make it look like it was a real wild fight. So, they had his shirt completely torn open.
All those buttons must have been ripped, right? Because they didn't unbutton them during the fight, did they? They ripped through the buttons, didn't they? Didn't they have to? They didn't unbutton them, one by one, did they? But, wait a second. Look at this:
The shirt doesn't look so disheveled there, nor does he. So, they let him comb his hair. But, the shirt looks buttoned except for the top button, but how could it be when the shirt was ripped open?
How do you go from that to this?
Here's another view:
Now, that shirt is buttoned except for the top button. Nobody can deny it. But, how was it possible after this?
The kindly officers didn't unbutton Ruby's shirt for the picture, did they? Didn't Bill Lord say that Ruby's shirt was "ripped" open? Ripped? That's what he said. So, it wasn't unbuttoned; it was ripped. So, if it was ripped, how could it then look like this?
Here's one more:
Now, for crying out, and for the sake of the Holy Virgin Mother of God, we can see the button there. It isn't ripped. Nothing looks torn. And it's not his jail shirt. We know what his jail shirt looked like.
So, what is going on here? How did Ruby appear in those neat, intact shirts after appearing in the ripped, disheveled one?
I could speculate, but why should I? It's not my problem. Let those who own it explain it.
What I know is that this is a choreographed image. It is the first image of the real Jack Ruby when he was thrust into the official story, when he, unwittingly, took over for James Bookhout. Welcome to the story, Jack.