Why did sern catch the protagonist and his party at the Stone Gate of Destiny?

The reason is that sern wants to suppress other institutions that study time machines to ensure that it is the only institution that develops time machines, so it uses mercenaries to kill these institutions by violence and steal their research results. After capturing d-mail, it began to deploy mercenaries in Akihabara, the birthplace of d-mail. In fact, they began to deploy after capturing the first article, but I think there are the following possibilities:1; In the game, the bald uncle Tennoja once sent two threatening messages to threaten the truth, because once he took action, mercenaries including himself would be killed, so the mercenary leader Tennoja didn't want to die, so he didn't take action. 2; Sern hopes to plunder together after the research of time machine produces more achievements, so the invention of jumping machine is such an opportunity. 3. Deployment and preparation take time.

According to Yu Meng, the second answer is more reasonable, but in fact, I personally prefer the answer of 1.

Party players want to adopt this game.