Buddies Back to Back

Senaka Awase no Nakama-tachi (背中合わせの仲間たち)

The silver spear made by Senku is revealed to be a sensor to detect poisonous gases coming from a pool of sulfuric acid, which they need for the antibiotic. Knowing the risks involved, Senku offers to teach Chrome everything he knows about science on the off-chance that he dies, but Chrome refuses, instead proposing a tag-team style approach. While gathering the acid using special gas masks, Chrome nearly falls into the pool but is saved by Ginro, who overcomes his fear and helps the duo obtain a bottle of the acid.