So in all seriousness while it may look bad that Titus is now a captive of the inquisition until such time as he can prove that he's not a heretic, I'm not sure Leandros is going to be well received by the rest of the chapter... and how would Marneus Calgar react to one of his captains being made a captive of the inquisition. While it is not unheard of for small units to be excommunicated, I would think the chapter librarians, perhaps Tigurius himself would really like to have a chat with Titus. Especially since they are supposed to weed out those with strong warp associations to make their way into the hands of the chapter librarius.
I'm just not sure what Leandros' decision is about, normally a space marine chapter prefers to keep these kinds of matters internal and not necessarily involve outside sources... unless of course Leandros is angling to move up in the ranks and needed Titus out of the way. Which, again, makes little sense because he may have either ostracised himself from the chapter... or with Sidonus dead, gives him opportunity to tell the story as he wishes.
Something of note was that even though a veteran of the chapter, Leandros showed little of the control which you would normally expect of the position. Perhaps he made it as a veteran for individual heroism rather than time in service?
Late night ramblings, so I hope that it makes sense.