Broken Vent Pipe

I need to replace my vent pipe and I was looking for suggestions.

It appears that the subfloor from the second floor bathroom has shifted just enough to lower the floor joist and break the vent pipe that comes off a toilet from the 2nd floor (see pictures in gallery). From here I see 2 options:
1) find a way to add a new vent line to the elbow piece (below where the current vent pipe is) so the new vent pipe can go under the joist.
2) reinforce the joist, then cut a hole in it in order to send the vent pipe through it. Keep in mind that the above subfloor has already sunk (I assume to past water damage) and it may sink further over time, so I'd hate to tunnel the pipe through the joist, only for it to break off again if the subfloor sinks further.

Any other options? Flexibility tubing etc?

That sucks right there,nothing but pure evil leaking out of that break. I dont know how you would go about that since they went fitting to fitting to fitting to fitting to fitting, sorry got carried away. If i had that at my house i would try a cut into those hubs and peel them off and then maybe cut high enough up towards the flange to get a shielded band on. You have no room to spread anything apart if you could somehow cut those fittings off. I guess you could take off the toilet and unbolt the flange and pull that piece up.

I would make cuts in the hub of the broken tee being careful not to cut into the street 45°. Then try and peel that hub from the fitting, could even try with a heat gun. It is not going to be fun thats for sure, good luck.

is there enough room to fit a right angle drill and a ram bit up there (ram bit) will drill out the pipe from the inside of the glued hub I would drill out the branch of the wye....
so you could start over......the above way sound good to just a though good luck

ram bit
a 3'' bit is about $50.00

Also, somewhere along the way, you want to look into jacking the failing joist(s) slightly(a bit at a time) and sistering joists along side the accessible ones. And/or getting a support under them, if at all possible.

You'll feel better about it the next time you're sitting on that toilet.