They have to win 4 of games. There is no one game they have to win. The do not have to win game 2. If they lose game 2, but wint the next 2 at home, what's the big deal?
They only need to win 1 on the road if they win 3 at home. Can be game 5 or game 7.
There are so many cliche things to say in sports, but they are usually just cliches. It is always better to win than to lose, but the only must win games are elimination games.