No. The way NVDA works is it uses a keyboard hook.
This intercepts all keys, and lets NVDA decide what, if anything, it wants to do with them.

However, sometimes NVDA crashes, or locks up. It's still accepting keyboard input, but not doing anything with it, kind of like how it works with input help mode on.
An example from a few months ago. I was looking at cell phone plans. Every time I got to a certain line in the page in Firefox, NVDA would lock up and do this.
Hitting windows+m to go to the desktop, then a character I know isn't the beginning of an icon name usually beeps, but it didn't. I knew my Windows sounds were working because I either restarted them or tested them earlier (there's a Windows bug that disables them on some reboots).

What can you do here?
1. Alt control delete works, and the NVDA there reads. You might think you can use task manager, but as soon as your session comes back, your keyboard still doesn't work.
2. Sign out. Hopefully this stops NVDA and leaves you with some of your windows open, for example if you had an unsaved notepad.
3. Switch to another user, kill the old NVDA process and switch back. You have to have that user set up before this happens, and I kept forgetting to make the account.