You probably heard the fast-speech version of the word, read like "soln". It's quite common in casual speech to drop the unstressed e in this environment. Generally I've heard the e dropped in words ending in -len, -ren, and even -nen (for example, my brother-in-law pronounces "Kolonnen" like "Kolonn" in fast speech). The z-sound at the beginning is instead a standard feature of Hochdeutsch (standard German): a single s is always (also at the beginning of a word) pronounced like English z, a double ss or the letter ß are always pronounced like the c in price instead. Some regional German variants, however, do have a "strong" (unvoiced) s-sound at the beginning of words.
At normal speed, I hear "Wohin sollen die Getränke?" At the slower speed it's "Wohin zung die Getränke?" I generally find the slower speed separates the words, which may be run together at normal speed, but except for sometimes being run together, the words are more accurately pronounced at normal speed.