Hello! Let me first say I've really enjoyed and appreciate all the professionals out there who take the time out of their day to respond. THANKS!

My question: I'm putting a bathroom in the basement of a house that was built about 5 yrs ago. There are several pipes roughed in already including a 4" pipe for the toilet, 2 - 2" pipes with p-traps underneath, and 1 - 2" pipe that has a t-fitting about 2' up from the floor and then continues as 1 1/2" pipe to vent. The system is below the waste line so the pipes run to an ejector pit. I assumed all the pipes went to the ejector pit, but not so. The one I was going to use for a shower doesn't connect to the ejector pit or the sump pit. I poured about 3 gallons of water down the hole, but I honestly don't know where it's going. I'm guessing I can't use that now and will have to bust up the slab and run pipe to the other 2" one with the p-trap that connects to the ejector pit. Please help, and any considerations for running the new pipe? I drew a picture to help also