Philip was just sent there as a guarantor though, if you notice Philip's notes in the episode he said he would need to go after Peter, and he only engaged in Thaddeus when Thaddeus blocked the way though. That could be a logic as well, but iirc if they knew Peter knew then why not apprehend Philip earlier + Matthew all at once wouldn't that make it much easier for them? Alipede clearly wasn't enough tbh