Bond again encounters Goodhead in Venice and observes her snooping around a door near the glass factory. Then he is chased through the canals by Drax's henchmen. He returns to the factory at night to investigate, and discovers a secret biological laboratory, and learns that the glass vials are to hold a nerve gas deadly to humans, but harmless to plants and animals. Chang attacks Bond, but Bond hurls him through the stained glass clockface of the Saint Mark's clocktower, killing him; during the fight, Bond finds evidence that Drax is moving his operation to Rio de Janeiro. Rejoining Goodhead, he deduces that she is a CIA agent spying on Drax and sleeps with her. Bond has saved one of the vials he found earlier, as the only evidence of the now-empty laboratory; he gives it to M for analysis, who permits him to go to Rio de Janeiro under the pretense of being on leave.