It is very likely that you are stuck in a place or traveling towards a safer destination in a group. It will be very helpful to use two-way radios in such a situation as it will provide an ease of communication among the group members. If one of the group members sees a threat advancing from one direction, he can notify other people to refrain from coming there and start moving towards a safer place.
These radios are either rechargeable or work on batteries. It is better to carry a number of batteries with you because you never know if you get stuck in a place where there is no electricity. You can expect the power to go off in such an emergency situation. A wiser option would be to carry a number of batteries along that will last at least six months. Honestly, I can’t see you finding a socket in the middle of a forest or in a refugee camp.