Reply to the following email with great humour and empathy and suggest how about reschedule it to Monday 2pm to not make her rush and make her laugh by the great humour:

Hi Ba,

Happy Friday! 

Thank you for scheduling a call, I have a meeting before which I feel is going to over run considerably so really wouldn't want to keep you waiting for me. Is there any possibility we could perhaps push this until next week? I can keep you posted on progress on when I am finished and if it does happen to be before our call but can't guarantee.  

All the best, 
Lorna