Tecmo apparently used the Dead or Alive engine for this game and didn't think this would be detrimental to the atmosphere of the horror game they were making. Other design and story choices are kinda dubious too. It's just annoying because this series didn't use to be like this
that looks to me like she's getting snapped 180 degrees because of animations or the camera fuckup, but it's been a while since i've seen "extra bounce" on doa 5.
I'm guessing her character model gets repositioned slightly for the cutscene, which to the boob physics system reads like she just moved at Mach 2 with inertia to match. This also happens any time you interact with anything.