First taste of cereal

I need to be careful of Robert around Hannah. However, I still need to shower so while Hannah is sleeping in her swing and Robert and Hailey are watching TV, I went upstairs for a little bit. While I'm changing, I hear Hannah screaming. So I ran downstairs to find Robert's cereal on the floor and Robert in front of Hannah trying to give her some. While I save Hannah from Robert, I see her spit out a little piece of cereal and went back to sleep.
A week before this incident, with similar setting, I came downstairs to a screaming Hannah and Robert on top of her on the swing. I know Robert loves her but just doesn't understand to be gentle.