Willian kept his eyes stuck to the book and he ignored the stuff happening around him. The message he sent to Rosa was delivered without any interference. He used the light spell same as the one he used to draw with Victoria. The only variance was that this spell can only be seen by those who have been tagged by the caster.
Encrypted short-distance magic. Rosa was smart enough to use the information to her use. She was a person who would develop thousands of strategies inside her brain and only use the one with the most success ratio. She would still have hundreds of backup strategies in case she encounters any anomaly. This sort of planning and execution needs a lot of patience and calm.
