HK travel insurance doesn't cover additional expenses due to travelling companion cancelling?

For example, if (A) has AMEX Canada Trip Interruption insurance:

Travelling companion - the person other than your spouse or dependent child who is sharing travel arrangements with you to a maximum of three persons.

Covered Risk:
The emergency medical condition of your travelling companion

Benefit:
Transportation - Reimbursement to you of the expenses you actually incur as a result of one of the insured risks up to the sum insured for the extra cost of:

D. Your economy class transportation via the most cost-effective route to your departure point.