Let's go through with it.

If the worst comes to the worst, we can both swim, I suppose, and we are not likely to get out of our depth." The chauffeur moved his head backwards.
"How about him ?" "He must take his chance," Gerald replied.

"He's all right where he is.
The car won't upset and there are plenty of people who'll see if we get into trouble.

Come, let's make a dash for it." The chauffeur thrust in his clutch and settled himself down.

They glided off along that winding stretch of road.