In this instance you did both. Sometimes room tone and ambiance are one in the same. That's what I was trying to explain. The main difference I guess is the mic technique used. Room tone is recorded with the same rmic/mics in the same position as when the scene or interview was recorded. Just no talking or fidgeting. Ambiance can be recorded like room tone, or with totally different placement and/or mics depending on what you're going to use it for.
The main thing is to think about how your sound will be used in post, and proceed accordingly.
Best,
Bernie

I would say you did the right move. The idea of room tone is so in post, when you take a continuous speech and cut it in the middle resulting in a gap -- "Give me the blanket, I'm cold" is edited to "Give me the blanket ..... I'm cold!" -- you have the same sound that is already in between the syllables of the words available to bridge the inserted space instead of just "dead tape." It serves to keep the speech from dropping out of the visual space and coming back in unnaturally. There was fridge hum during the dialog so it would sound unnatural for it to be missing during any pauses inserted in editing.

So were you actually IN the fridge? No wonder you could hear it humming.

:-)

Hi All,
I would like to ask a question regarding the use of roomtone in post.Lets say in the edit suite one was to take the roomtone recording which includes the fridge noise and reverse the phase and then mix it with the original recording, would the fridge noise be then silenced by phase cancellation? Thanks in advance,Neil

In some cases, but not usually with dialog on the same track.
That's the principle of many of the NR tools and why they're costly.