They were starting to run out of penicillin, so what they would do was run with his urine across the road to re-synthesize the penicillin from his urine and give it back to him, and that worked.
Comenzaba a agotarse la penicilina y entonces procesaron toda su orina para resintetizar a partir de ésta más penicilina y dársela de nuevo, y eso funcionó.