No, it is impossible for Swan to move Bitcoin from your Vault without your participation because Swan has access to only one key and two are required to move your coins.
Swan Vault utilizes a 2-of-3 multisig structure. This means at least two keys are required to move your Bitcoin. You hold two keys via your signing devices and recovery phrase, while Swan manages your third one, your cloud key. Also, since you hold two keys, Swan can never prevent you from accessing your Bitcoin. You retain full control.