how about this?

Sub-dermal implants in hands, originally designed to assist rescue crews find trapped victims and navigate rubble. these implants can detect sound and temperature through walls and doors giving a vague diagram of the room up to 10m from point of contact. voices and footsteps depending on distance also register, within 2m footsteps will have a marked location within 30cm of actual origin, and growing less accurate from there, any audible voices within the 10m radius will be marked within 2 of actual origin.