Seems like there might be some clarification about the "death" part tomorrow, but I will be on a trip starting tomorrow until Tuesday, so if someone can help translate this series, that would be appreciated. If I managed to get internet and have time, I'll try and sneak in :).

Mastine said:

Previous strip she was saying she should talk with him about life. Then immediately asks about death.

She's nervous. Give the girl a little break.

Anyway the reason why she said she made a mistake because she thinks he could read her mind and know that she wants to talk about life(which he couldn't).