I can't understand where this myth has come from - its virtually impossible for the matrix to burst - then spray boiling water onto your legs!
If the matrix does burst, it hardly happens with explosive force - the cooling system is barely pressurised. Then the fact it would have to somehow just break through the walls of the heater matrix housing - which couldn't happen. Then when it does leak, it would just drip out the bottom of the heater matrix housing only once it has filled up about an inch from the recess at the bottom of the housing.
Even if the matrix housing had a hole in it - there is a plastic cover between the matrix housing and the drivers footwell too!
@the chicken guy - don't bother with bias valves, just remove and bridge with copper pipe, and if your not a pikey like the rest of us, you can buy the replacement hoses from gsf/vw and a new matrix from gsf/vw (gsf one is OEM Valeo)