Can a reasonably healthy pet pass away under anasthectic?

To our knowledge, apart from a bad leg and a little bit of hearing loss, Tigger has not got any other health conditions (vet has so far not said about anything concerning)

could she still die under the anasthectic they are doing to her while they check her mouth? its been almost all day and i'm scared in case something's happened and she's died under anasthectic

i dont want to start googling cause thats a rabbit hole that will only make me worse