Modifier problems.

Hi Guys,

Please help me understand the solutions provided in MGMAT problem set question nos 14 and 15 of chapter 6-modifiers.

Q. 14. Last night our air conditioner broke, which caused great consternation.
Q. 15. The patient's rare disease was treated using novel techniques developed at the medical schools.

Sol. 14. Last night our air conditioner broke, causing great consternation.

Great! no issue, as we cannot use 'which' to modify the event of 'breaking down of air conditioner'. Hence, the modifier was changed to modify the verb by using participle 'causing'.
But in the next question, MGMAT defied the previously applied logic by saying that the sentence is wrong! It says 'using novel techniques' is a case of dangling modifiers, as the sentence contains no noun that is properly modified by 'using novel techniques'. Why cannot we apply the criteria of Q14 and say that the clause 'using novel techniques' is a verb modifier and it is modifying the event of treatment of the patient.

will be thankful for any reply.
Cheers!