Whilst in theory the jet of steam might put out a locomotive fire, in practice it seems not. The jet of steam tends to be carried straight through the tubes, and is gone. The noise of escaping steam might draw attention to the problem, especially if the crew is already aware they have a water feed problem, but laying on the cab floor attempting to look up at the crown sheet, with a brick arch obscuring the view and your eyeballs being roasted by a ton of burning coal can make identifying the leak rather tricky.
Sadly, in practice, for a locomotive to have got into such a fix, often the crew is convinced that the water gauge is correct, when it is in fact faulty, and draw the conclusion that the other gauge, or the try cock, is giving a false low reading when it is in fact telling the truth. In such a huya state, the noise of steam released from the fusible plug is mistaken for a leaking tube. There were a number of S160's, (the USATC 2-8-0 built for europe in WW2, you might call them something else) operating in Britain, post war, where the crown sheet failed due to low water. The fusible plugs melted, and in at least 3 cases, the warning was misinterpreted with catastrophic results.
The low water issue on these locomotives was caused by the valves of the US design of water glass operating very differently to British practice. That and the fact that Alco decided to hide the single gauge glass behind the gauge lamp, the try cocks behind the throttle quadrant.