There were likely a rare few people on Earth that had the flexibility of thought that Sylas did. The moment he realized the kind of situation he was in, he changed his perspective.
He didn't worry about finding Lucius for revenge, nor did he have the mind to care about what people were watching from the shadows. Instead, his thoughts were consumed by one drive.
Survive.
The instant he got the notification about what was happening to him, he activated Beacon. And it was actually because Beacon was activated that
Beacon needed to use his Beast Totem. So while it was active, his Beast Totem couldn't be used for anything else.
But the miraculous thing about Beacon was that the only existences that could sense it were Serpentes. As such, whether it was the spider queen or the Sylphs watching from the sidelines, they didn't realize what he was doing until it was too late.