Panels from Marvel Mystery Comics #3 (January 1940), script and art by Bill Everett
We immediately discover this butler's name is Pinkerton...
...which can only mean one thing: Sub-Mariner has wandered into Madame's Place:
Anyway, that fire. Just like an Ellery Queen mystery, let me pause for a moment to let you attempt to figure out the solution to the mystery. (Ignore the screaming burning woman for a while; she'll wait while we examine all the clues.) You've seen everything Namor has, and you know all of Namor's special superhuman powers, right? So surely you know how he will save this damsel in dis dress! Go ahead...match wits with Namor McKenzie...and see if you can find out...how he duz it!
Got the answer yet? Let's see if it matches Namor's clever plan of action!:
I...I did not expect that. Ummmm. What did we just see, comic book?
Oh, that familiar old cliché Subbie trick! Why, I do believe we've seen him, in hundreds of comic book appearances, repel excess water from his pores. That certainly comes in handy every time he fights Johnny Storm, and, if, say, the Secret Invasion had not been by Skrulls but instead by those aliens from Signs, why, we'd all be bowing down before Lord Namor, king of America, instead of our pal Norman Osborn.
Just in case you missed it, Pinkerton asks Sub-Mariner to explain just what happened two panels ago:
To which Namor replies with his usual tact and grace:
So. Namor. Can flash-flood through his skin upon application of extreme heat.
I so wish Roy Thomas had restored that power!