You just created not correct rule. Its all not about "first o" or "second o". Its about is "o" under the stress or not. If it is under the stress, so you say it like "o". If it is not under the stress, you say it like sound between "э" and "a" (actually you have this sound in English too).

When stressed, /о/ is pronounced as [o] In the syllable immediately before the stress and in word-initial position /о/ is pronounced as [ɐ], similar to English 'nut' In other positions, /о/ is pronounced as a short [ə] Eg: молоко [məlɐkˈo], облако [ˈobləkə]

Both O's in this word are in a weak phonetic position (the vowel И is in a strong position, it is stressed), so they both sound more like ah.

I'd make it simpler and suggest using schwa for "a" and both "o" in this word.

Hello, Jenny! I am afraid that there is no such rule in Russian: "Ok, so as I recall in a word that contains more than one "O", the first "O" usually sounds more like "ah" and the second "O" sounds more like "oh". However, I also recall that sometimes there are words that don't follow that rule." it's not about the position, it is about the stress. Common mistake: молоко́ / molokO / под столо́м / potstolOm /* дожди́ /dozhd'I / Vowels can be either stressed or unstressed. The unstressed vowels undergo the reduction effects. One of the most important quality reduction effects is called "А́канье": Unstressed letter "о" should be read as / а /. * note that the prepositions in Russian in 99% of cases are unstressed and connected to the following word. Correct usage: молоко́ / malakO / под столо́м / patstalOm / дождь / dOzht' / => All the 'O' letters in the word "неожиданность" should be read as reduced / а / Hope it helps! Евгений