EC135 / EC145   

the potential for a fire!  BTDT, not my doing, but had to clean up the mess - took four months to get the helicopter back, and then just barely as assessment of duration of fire (exposure timelines)was the key to whether it would be scrapped.  

And, make sure the heater output is not going to overheat internal structures, cabinets, semi-loose articles etc. 

Dicey stuff if not very careful!  If the med crew does something in the helicopter go out and check if they have dislodged the heater/s.  They tend to be very careless about that stuff.  

Don't underestimate the extent to which your pilots do understand and will effectively deal with cordage in and in/out of the aircraft.  

No need to jam doors, just use a window with a hard foam H insert with Remove Before Flight tab to cover the open bit remaining.