This particular intersection is an at grade crossing of a major state highway. this intersection will likely become an over/underpass in the future as the road is planned to become a toll road. Until then, you have 70+ mph traffic having to stop for a traffic light. I expect that running the red light is a common problem and, according to a post on another forum, may have been the cause of the crash.
Because this is a state highway, the local government almost certainly has no authority to make any changes, including adding a bike lane to the wrong way underpass as suggested by the OP. Any accommodation to cyclists probably needs to be worked through TXDOT. Perhaps the OP could get the Texas Bike Coalition involved to push for creating a bike lane using the suggested underpass. This seems like something they might take up.
Until then, the best thing for cyclists using this intersection is to hesitate a few additional seconds and make sure that cross traffic is actually stopping before entering the intersection.