It says on the zzzquil label that there is 10% alcohol in 354ml. is taking a dose of 30ml of zzzquil equivalent to taking a shot or drinking a beer?

No: If Zzzzquil is 10% alcohol then 30 ml has 3 cc of alcohol. An average beer is 12 ounces or 360 ml which is 4-6% alcohol which thus has about 20 cc of alcohol and a shot has about 20 cc of alcohol as well. Thus Zzzquil has the amount of alcohol as about 1/7 of a beer or shot but does have diphenhydramine, an antihistamine that makes you drowsy, so it is not wise to take more than about 30 ml.