All I can say is that as a SLF, if I heard what was on the PAX video (with the accompanying light flashes), I would be more than a little startled and concerned. Is such an occurrence sufficiently routine and/or distinctive that the pilots would have been both unalarmed and immediately fully knowledgeable as to what occurred? I stand ready to be corrected, but I would guess not. Thankfully, the incident appears to have occurred early in the roll at relatively low speed, so all ended well.