Coming from the South Eastern region, I remember the days before Tightlock couplers - when stations like Tonbridge (where third rail EMUs split & attached) had a permanent shunter on duty.
He had to go between the units in the platform as they 'eased up' to trip the buckeye and remove the air pipe and brake pipe.
They never seem worried about the risk of being electrocuted or crushed between the units - nowadays of course Elf & Safetree would never allow it.