The discussion revolves around the confusion regarding metric prefixes, specifically trying to convert 2 mL into 200 L. It is clarified that 2 mL equals 0.002 L, with the prefix 'milli' denoting one-thousandth. The conversation highlights that combining prefixes, such as 'centimilli' or 'decimilli', is not recognized in the International System of Units (SI). The participants emphasize the importance of adhering to standard SI conventions and criticize the use of unconventional prefixes found in some educational resources. Ultimately, the need for clarity in metric measurements and adherence to accepted standards is underscored.