Level 2 - Hint 2
You can find the account ID with the session token you acquired in level 1 and calling:
aws sts get-caller-identity
All of flaws2 runs out of us-east-1. You can then list the images with:
aws ecr list-images --repository-name level2 --registry-id 653711331788
You can make that call from any AWS account from a user that has ECR privileges. Since I'm nice, I gave the level1 role privileges to make that query (and others to complete this level) if you don't want to do it from your own account.