ACTUALLY, it is safe to mix
2mg kpins with 200mg tramadol and 2mg bupe. Even if you didn't have a benzo tolerance at all, this would do little harm to the vast, vast majority of people. And if he/she has any experience using benzos, well, I can pretty much guarantee they won't have any problems whatsoever.
You are right, people need to be careful when mixing benzos and opioids, but given what this person is specifically do, they are mixing them in a relatively mature way, and if nothing else at not inappropriate dosages.
Shiiiit I'd LOVE it is they started using tramadol as an anti-d. It certainly works way better than anything else I've ever had for depression. Then again, I'm set for the foreseeable future given how well bupe works for my depression/anxiety