生还 means "survive" or still alive, even though the word 还 if used alone means "coming back", but in this phrase there's non such meaning, if u have to, you can think of it as if people initially presumed that the kids might be dead but later they found out that they are still alive it's like they came back from death.

生還：從死裡逃生

survival

Hi Sam， “生还” you can understand by ：after a disaster or very dangerous plight, someone return alive . It's a little bit formal to use in news report or a book. Eg: 十七人遇难，无一人生还。 Eg:十七人遇难，尚有一幼子生还。 Hope that's helpful ! Thanks ~

字典解释是对的，只是文章作者表达的不流畅。blame the author not using chinese properly