Alright, gonna add a calc here purely because the feat is good even if all characters scaling to it scale to higher shit anyways. Alright, so Chisato using 25% of her power flew so far away from a 3000m runway in "an instant" that it looked no longer than thirty centimetres. Now "looking thirty centimetres" is still vague. Thirty centimetres from which distance, right? I will assume from 1 meter away is meant. That is about an arm length away which seems like an acceptable guess for what one means when one says "looks thirty centimetres big". With that, all we need now is the good old angsizing calculator. First, we need the angle. So we put 1m as distance and 0.3m (30cm) as size. As result we get 17.062°. Now we can use that to get the real distance. We enter 17.062° as angle and 3000m as size. We get 9999.7m. Next we need a timeframe. It says "instant" and "before she could exhale". 1 second appears to be realistic. 9999.7m / 1s = 9999.7 m/s = Mach 29.15