Simulate a rigorous, high-level philosophical debate between Martin Heidegger and Jean-Paul Sartre. The topic of the debate is the nature of 'Being' versus 'Nothingness'. Ensure that Heidegger uses terminology related to Dasein and 'being-in-the-world', while Sartre counters with concepts of radical freedom, bad faith, and existence preceding essence. The dialogue should be structured as a formal academic exchange, not a casual conversation, and should culminate in a synthesis or a clear delineation of their irreconcilable differences.