Strong lensing offers a precious opportunity for studying the formation and early evolution of super star clusters that are rare in our cosmic backyard. The Sunburst Arc, a lensed Cosmic Noon galaxy, hosts a young super star cluster with escaping Lyman continuum radiation. Analyzing archival HST images and emission line data from VLT/MUSE and X-shooter, we construct a physical model for the cluster and its surrounding photoionized nebula. We confirm that the cluster is Myr old, is extremely massive and yet has a central component as compact as several parsecs, and we find a gas-phase metallicity . The cluster is surrounded by of dense clouds that have been pressurized to by perhaps stellar radiation at within ten parsecs. These should have large neutral columns to survive rapid ejection by radiation pressure. The clouds are likely dusty as they show gas-phase depletion of silicon, and may be conducive to secondary star formation if or if they sink further toward the cluster center. Detecting strong 1750,1752, we infer heavy nitrogen enrichment . This requires efficiently retaining of nitrogen in the high-pressure clouds from massive stars heavier than up to 4 Myr. We suggest a physical origin of the high-pressure clouds from partial or complete condensation of slow massive star ejecta, which may have important implication for the puzzle of multiple stellar populations in globular clusters.