Uh oh... too much dissolved gas in my water?

I was doing a water change recently and ran into a problem: I had to put my newts back in my 10 gallon tank to make it on time to an appointment, but the water I just filled the tank with dropped the temperature to 65 F. The water they were currently in (a holding tank) was around 72 F, so I put 1/4 gallon of water (from the tap, treated, and left to sit for 24 hours like the rest of the cold water) into my kitchen kettle and made it VERY hot (it is an electric kettle, so I left it on until it stopped on its own).

The added 1/4 gallon of water brought the temperature in the tank back up to 72 F. However, I read here and there that rapidly heating water will cause it to be dangerously rich in dissolved gas, including nitrogen, so I'm a bit worried about gas bubble syndrome. I added the water to the tank slowly over the course of about a minute, and then added my newts and fish about 10 minutes later.

Since the water was treated and left to sit for 24 hours prior to being heated, I would assume that the dissolved gasses were at a safe level before heating the water, and thus the heated water probably wouldn't have too much dissolved gas in it. But I don't think I'd bet my pets lives on what I've pieced together on the internet, ignorant factors I may not have read about yet, such as whether cold ungassed water becomes gaseous under extremely quick heating.

So, my question is, do you guys think my dissolved gas levels in my tank are likely to be fine? If it helps, again I have a 10 gallon tank which is mostly filled, with penninsula newts (hence the high temperatures), and a standard underwater tank filter on a low setting.

I wouldn't worry. Heating water is likely to reduce dissolved gases, not increase them. Solubility of gases in water decreases with warmer temperature.
Also, I doubt that a temp drop from 72 to 65 degrees would bother your newts all that much. That's not a very big difference.

Thank you very much, I'm glad to hear that!

As far as the temperature difference... I've got neon tetras I had to put in there too, so I was mostly worried about them, would they be alright too do you think? Thanks for the info, a good thing to know.

I've had some neons at that temperature and they were fine, but they would probably like it a bit more tropical....

However, it's not a good idea to have neons with newts. They do need different temperature conditions. Which species of newt do you have? Almost all newt species are happiest at less than 70 F or so, whereas tropical fish prefer warmer temps.

I have three N. v. piaropicola. These newts are only found in peninsular Florida, which has pond water temperatures that get much higher than 72 degrees. Since there isn't too much information on peninsula newts in particular, I'm really unsure about what temperature I should keep them at, though I imagine it should be much higher than a typical eastern newt from, say, New York. Any ideas on this would be most appreciated.

Ya, the tetras don't really belong. But they seem to do alright, and considering I first purchased them to see if my newts would eat them (they tried for days, but gave up in the end), they now function as not only a tankmate but also an indicator species of sorts. For example, if my dissolved oxygen content is low (which I was worried about when I first got my tank), I will be able to see it much sooner in the tetras than in the newts.