Almost simultaneously.

Roget 113: instantaneously etc. adj.; in no time, in less than no time; presto, subito^†, instanter, suddenly, at a stroke, like a shot; in a moment etc. n.. in the blink of an eye, in the twinkling of an eye, in a trice; in one's tracks; right away; toute a l'heure [Fr.]; at one jump, in the same breath, per saltum [Lat.], uno saltu [Lat.]; at once, all at once; plump, slap; at one fell swoop;" at the same instant etc. n.; immediately etc. (early) 132; extempore, on the moment, on the spot, on the spur of the moment; no sooner said than done; just then; slap-dash etc. (haste) 684.    ... show more

Roget 120: at the same time; simultaneously etc. adj.; together, in concert, during the same time; in the same breath; pari passu [Lat.]; in the interim; as one.    at the very moment etc. 113; just as, as soon as; meanwhile etc. (while) 106.    ... show more