Should timers pause during checkout?

As an e-commerce manager, I'm trying to understand the best practice for handling countdown timers during the checkout process. I want to create a sense of urgency without frustrating customers or causing anxiety during their purchase journey. Should the timer continue counting down while a customer is completing their checkout, or should it pause to give them a fair chance to complete their transaction? This decision could significantly impact conversion rates and customer experience, so I need a strategic approach that balances psychological motivation with user-friendly design.