My guess is that this is no bueno.  Happy to be proven wrong.  

That would make me nervous. 

Abort. 

A few things.

This may seem obvious, but sell by/best by date on anything vacuum sealed/cryovacced is based on the seal being in tact. That said, if it wasn't in tact when you bought it, it's no different than if it was just in a foam tray, which has a shelf life of ~4 days. 2 weeks...no good.

Wet aging is essentially leaving beef in a cryovac package (own juices) for a normal aging time of about 21 days. Depending on the pack date of what you buy, it's almost all wet aged since the shelf life is generally +3 weeks even if it isn't labeled as such.

It seems you've already identified this as a problem, but the ballooning is not good. This sometimes happens with vacuum sealed meat, particularly poultry from my experience. A lot of vacuum sealed meat can give off a "gassy" smell when first opened, which is normal. I think it's the byproduct of wet aging, but the ballooning means there is an excess buildup of gas. If I ever pick up a whole chicken, turkey, or package of either and it is ballooning, I put it back. It might still be good if the package isn't compromised, but I stay away.

I've never seen that happen on any cryo packed protein. Good call tossing it.

Don't feel too bad, @DoubleEgger tossed a SRF (cannot remember the label color) at one time.  

Lit said:

The Cen-Tex Smoker said:

To the guy grinding his own medium rare burgers with a Costco Brisket because it's safer than commercial ground beef...

This can happen anywhere. I still trust grinding my own Costco meat over any butcher. I personally watched a local butcher trimming meat for over 2 hours and tossing the scraps into a container that was out on the counter then he made ground beef and threw those trimmings in with the meat he was grinding. 

I do it too but just showing that the outside of meat can (and probably is) contaminated no matter where you get it. 

I've never had issues that I'm aware of but grinding beef and eating it med rare is risky. Not the end of the world for most healthy adults but you are most likely in for an unpleasant day or 2 in your life if you do this regularly. 

If I liked it better than smash, I would still do it. I just prefer smash and it has the bonus of being safer

Did you poke a hole in it? Did it make a satisfying "pssssst" sound? Did you vomit when you smelled it?

I'd have poked a hole and then left it lol  An aromatic reminder of their fail.