We don’t know enough to determine if he used the spray before and or just during the mauling.
With practice, one should only need 1.5 to 3 seconds to deploy a firearm or spray if holstered if one has it in hand more like 3/4 of a second to deploy and get hits.
With most bear attacks one has more then a few seconds to realize what is going on if paying attention.
The key in any defensive situation is to recognize early that one might have to defend oneself. Thus giving you a change to deploy your defensive arms or get ready to.
I have heard over and over from people who have been attack does not matter by what or whom I didn’t realize or think on could happen to me.
Be alert, practice and prepared.
riverrunner is correct. unholster that hogleg if you even feel a bear is near. You can always put it back.