The dragons run a money lending agency for supernatural beings. (If you accept vampires and mutants, its really not that big a jump to also accept dragons :p)

The pocket dimension is used as a safe by the dragons to lock up their payments and anything given as collatoral for loans. Stuff is moved to the pocket dimension by magic transporter necklaces.

Hot Vampire Lady was a client, who owes the dragons a lot of money and is in financial trouble. But she can get the stuff she submitted as collateral back if she gets hold of one of those transporter necklaces, and outright cancel her debt if the zombie accountant is killed.

But to prevent that from happening, both the transporter necklaces and the accountant are kept in a high radiation area.

So Hot Vampire Lady uses Jubilee as leverage to force Wolverine (who’s healing factor protects him from radiation) to go get the transporters. She knows that even if Wolverine does not give her the necklaces, he’ll be forced to kill the accountant to use them (the activation ring for them is inside the accountant’s head).