It was probably one of the nicest ways someone has chastised Senku in a manner that he actually got that was what they were doing.

"I want to help." Senku told him honestly. "It's interesting to me, sure, but it's also not my world and doing something that's going to be a problem for you isn't my intention. If you don't want that, I can respect it."

He exhaled. "But, that aside, whatever else comes up on this train, no one's gonna let you sacrifice yourself before your time." That was a promise he wouldn't back off of.