I feel that he shadow is very much distracting in the first shot. I would keep the flash on camera and bounce it, soften it up and go higher in ISO like 3.200 and stop down to 2.8 the adjust the BG light with the shutter speed to desired levels
Why underexpose?
Bounce was not an option, the ceiling was painted black
Similarly the back ground was, apart from the spill light from the foyer, deprived of any type of serious lighting, so bumping up the ISO and opening the lens would not have mattered .
And of course 2.8 would mean loss of DoF, which considering the already considerable risk of unsharpness (fast moving subjects under for all practical purposes non existant light) was a risk I wasn't prepared for.
Also, using just one speedlight would not have given enough GN, and consequently range and recycle times, to cover the whole catwalk (around 35 to 40 feet long).
So consequently using at least two speeddlights was inevitable, the combined weight of which, together with the external PB960 battery pack, with a D800 and grip, and 2.8/70-200, are impossible to handhold/operate comfortably for a longer period/speedily during a shoot (even if the whole contraption was e.g. mounted on a monopod, which BTW is what I always, just as in this case, use when shooting catwalk with the 70-200)
Positioning the speedlight(s) flat out in front of the castwalk was of course impossible, as I was already was standing there
Due to the relatively small space between me and the front of the catwalk, there was no room to put there either, and placing them straight behind me would course would risk me be blocking them, or creating a big shadow covering the oncoming models.
Under exposure allowed to keep initially the contrast low, in particular after recovering the shadows in post, which I then could later augment according to my personal preference while making the definitive version of the picture in post