Mouse is first introduced in “A Beautiful Friendship” as Jay’s CI, assisting him with a case. The two seem to be very close, although no one explains why or how, and he is not seen again until the next season.Click to see full answer. Subsequently, one may also ask, what episode does Mouse join Chicago PD?Mouse was a guest star in the first season episode “A Beautiful Friendship” before becoming a recurring character in season 2. By the start of season 3, he had settled into his role with the team comfortably, overcoming what Hank Voight (Jason Beghe) thought of him at first.Similarly, are Jay and will Halstead brothers in real life? Today’s reason: Chicago PD’s Jay Halstead (Jesse Lee Soffer) and his brother, Chicago Med’s Will Halstead (Nick Gehlfuss). The Halstead brothers are one heck of a One Chicago double act. They’re both interesting in their own right, but we also genuinely enjoy seeing them together. In respect to this, why did the character mouse leave Chicago PD? As we know, the Intelligence Unit’s resident tech analyst, Greg “Mouse” Gurwitch (Samuel Hunt) asked Voight to write a letter on his behalf in order to have a felony record buried so he could reenlist in the army, and Platt wrote it instead. But what we didn’t know for sure was if Mouse was really going to leave.Did ruzek leave Chicago PD?With the “Chicago P.D.” intelligence unit fried following Upton’s time in quarantine, and Halstead’s near poisoning, the team disbanded as each officer sought some downtime. Two of them – Burgess and Ruzek – went off together. And just like that, Team “Burzek” was back in business.