There shouldn't be any issue with the xan as 6 hours is enough for it to wear off, but just don't go to sleep until 3 hours at least after the oxy to make sure you are not feeling any respratory depression. If you do start feeling difficulty to breathe call emergency services. If you find yourself losing concsiousness before they get there make sure the door is unlocked and if you can write a note stating exactly what you took when so they can respond properly if needed. Really though you should be okay, but these are just suggestions....
If it's a formulation you can break into a snortable powder by just crushing it and then do 5mg worth bumps every 15 minutes until you feel better. I personally found oxycodone most effective used nasally where 15 mg could get me nodding while a 30 mg ER formulation, which should be equivalent yet only manages my pain even if I chew it to get a more immediate release. Injecting was honestly like injecting water with oxycodone... It might slightly build, but I do large amounts of it IV and barely feel anything. It took 120 mg or however much would fit in a ml of water to actually feel oxycodone IV... I may be an outlier, but it was definitely useless injecting it while nasally was insanely strong Rhe only explanation I have is it absorbs as much as possible as fast as possible while still putting it through the metabolism to convert it to oxymorphone, but I could be completely won't as I really don't understand it honestly