instantaneously

At the same instant his ear caught a sort of indistinct sound on the stairs, followed by the measured tread of soldiery, with the clanking of swords and military accoutrements; then came a hum and buzz as of many voices, so as to deaden even the noisy mirth of the bridal party, among whom a vague feeling of curiosity and apprehension quelled every disposition to talk, and almost instantaneously the most deathlike stillness prevailed.

For you must indeed be a great chemist, and the elixir you administered to my son, which recalled him to life almost instantaneously——”