The morning after the proposal
When Sister Angela goes to speak to Cpl. Allison the morning after he proposes, is it possible that she's changed her mind and is going to accept him? He doesn't give her a chance to speak. He just launches into his speech about how a Marine should never get married (which is probably b.s., to cover his pain).
When he walks away, she looks pretty upset. Was she disappointed, or is she just feeling sorry for him?