SKS Key fob usable with dead battery???

Hi folks,

I recently had an eardrum-blowing event with my Prius....

After I pulled the key fob out of the slot and got out of the car, the alarm suddenly went off. I tried to push the Lock and then Unlock buttons multiple times to turn off the alarm but that didn't work. After I re-inserted the fob into the slot, the alarm turned itself off. Trying to lock the doors, I noticed the remote functions (Lock, Unlock, Panic) no longer work. When any of these buttons is pressed, the red LED light on the fob no longer lights up. However, I can still open the car doors/trunk with the fob in my pocket as well as start the car w/o inserting the fob into the slot.

Is the battery in the fob dead? If yes, do the "smart" functions continue to work with a dead battery?

PS: If the remote Lock/Unlock/Panic buttons is all I give up, then that's fine. I don't care to replace the battery every 1.5-2 years, even though I can do it myself. The "dumb" key fobs for my other cars (14 yrs old, 8 yrs old rechargeable) are still on their original batteries.

 

I like multiple guess answers. #1 is correct... the 'panic' button was stuck. All buttons work now.

Thanks!