I've been wondering about something similar for a while too. Before deciding anything, notice the 1st time Col. Titan transforms is slightly different than the 2nd time. The 1st time involves ground-shaking. The 2nd time, he just simply appears. For the 2nd time, I wouldn't doubt Isayama can easily make the ground shake like the 1st time: "After Eren finishes his monologue, the ground shakes and falls on his butt. He turns around to see the Col. Titan."Ramdom question. Is it outed anywhere how RBA got into the walls in the first place? They have been pretty young (inb4 becoming a shifter completely halts aging) at the time and while the colossal was near the gate, he couldn't just go back to human form and enter the gates. What's more, none of the three had access to 3DMG so they could not really climb the walls as well.
Of course, the difference of having and not having the shaking of the ground can merely be dramatic licensing instead of some profound logic, but if I had to try and explain that, I could only say, Bert must have transformed as he landed on the ground. How could he have 'landed?' Well, he must have jumped off from somewhere high.
The other difference is, Col. Titan doesn't show his face immediate the 1st time after the transformation. He shows his face immediately after the flash of light the 2nd time. If he had landed from somewhere high, it would be possibly imperative for him to land in a crouching posture with one hand on the ground for balance. Of course, it could be dramatic licensing again, though if it were supposed to have an explanation, that's what I would say.
And my last point is, I still can't figure out if Bert transformed on the ground, would he be teleported straight to the nape? Or would Titan body grow out from him, and push the head part (and therefore himself) upward? We have seen Eren's protection transformation, where bones and muscles build progressively outwards (from the centre of his body to the fingertips.) If Bert transformed on the ground, it would just be the same for him as anyone else (getting pushed upwards by the spawning of Titan body.) But I'm just curious if the ground-shaking bit at the beginning has something to do with anything at all.
Final final point, I'm also curious as to how Bert reverts back to human. If he didn't have 3DMG, then shouldn't he lie down as with the nape as close to the ground as possible to avoid falling injury?



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