Water leaks under viking professional and there is about a 1/4 inch build up of ice on floor of freezer(which is on the bottom) on the floor of the pull ot freezer

Your drain is plugged. Basically the freezer goes into defrost and melts frost off the condenser coils. A big piece most likely fell off and freezer came out of defrost before it coulld melt and drain out completely. To fix you have 2 options. Have towels
#1- move contents of fridge and freezer to a backup fridge. Leave unpluged with doors slightly opened for 24 to 48 hrs. Use towels to cleanup any water. Plug back in wait 2 hrs to make sure temp gets back down before putting contents back in fridge.
#2- Remove contents from fridge and put in ice chest. Have towels ready. Remove ice maker ( if there is one) usually two screws on top hard to see and one on bottom. Disconnect the quick connect for the ice maker. Remove screw on back wall. Be careful when removing air vent on back wall. Its plastic and can break. Remove back panel. Look on the silver plate under coils and you will see ice and where the drain is. Remove ice than pour hot hot water down drain until it flows freely into drain pan under fridge by compressor. It may look like there is not ice make sure othyerwise you will be doing this all over again in a few days. Once water flows freely put everything back together wait about 2 hrs for freezer temp to get cold enough and than you can put contents back in freezer. If you have any question or need help please feel free to comment me back.