@Nk9bjP4A
I think that ‘that’ aspect of it's ability won’t be explained (unfortunately). It’s clearly this way so that the protagonists can win (otherwise it’d be impossible). If I had to guess, it’s less tasking to have a single designated spot, rather than constantly assigning it, while aiming at the target.
I must say though, the explanation isn’t 100% accurate. It’s not required for two objects to swap places. Most times, when EX-ARM 13 is used, it only teleports away the targeted area without doing the spacial exchange. The one with Leon, in the flashback, was exclusively done for the sake of him figuring out 13’s ability. The only thing you could say it exchanges, is air which is, of course, possible and must be happening.
I wouldn’t say it’s a bullshit limitation, or that the protagonists will get an easy win. It all makes sense, at least to me.