How could she not know the camera was in there when the camera was in the hall and the few items of clothing that were all that was part of that wash load were in the bedroom? She HAD to know that camera was part of the wash load just in gathering up the things to put in the washer. There were so few items in there with the camera she had to have seen it in the washer before dumping in the bleach and soap and starting the machine.
I don't think she was in a frenzy at all after the murder. She was meticulous and calculating in what she did... trying to clean the floor, washing off Travis's body she dragged back to the shower, washing herself either in the tub or one of the downstairs bathrooms, stripping the bed and washing all the linens, deleting all the photos from the camera one by one, gathering up the clothes he wore that day that could have her DNA on them and the camera that was in a separate place, putting them all in the wash and dumping in bleach with them (the wash load of linens hadn't been washed with bleach), gathering up the murder weapons and all her other stuff to leave the house, etc. And all that time she was playing Beat the Clock to get out of there before the roommate got home.
She put the camera in the washer on purpose... there was no other reason to delete the photos and wash it other than to make it look like an innocent camera that she would have meant to put back into its case but she ran out of time. She probably did end up leaving before that wash cycle with the camera was finished because of running out of time. But the camera was in a different place than the other items that were in that wash load, and there were so few items in that wash load she couldn't have missed seeing or feeling the camera.
There was no other reason to delete the photos one by one than the intent to leave the camera behind, and if she intended to leave it behind than it would need to be cleaned of blood and fingerprints and the memory card destroyed. She had less than half an hour to do everything she did to try to erase herself from the crime scene, clean up her own self and change clothes, and get out of the house before the roommate got home, and to use part of that time to delete all the photos means she didn't intend to bring it with her. His camera being the only thing missing from the house would have pointed the finger at her. Had she had a little more time she would have removed everything from that wash cycle, made up the bed with the clean bed linens and put the pristine camera back in its case.
In hindsight, it would have been smarter to take the camera and a few other items, trash up his room a bit and make it look like a break in, but she wasn't thinking along those lines. She was only trying to erase herself from the scene by getting rid of her fingerprints and DNA from the scene along with the incriminating evidence of her at the scene because of having taken the photos and clean up herself so she could leave and not be noticed as having blood on her or her clothes while driving out of the area. All that she did after killing Travis was meticulous and calculating but she ran out of time before she could get the camara out of the washer and back in its case. Had she had the time to do that it's doubtful that LE would have thought to examine the camera or even notice it at all as something significant.