Gainsey,
That would be the string connecting all the safety pins together so when you took them out, they would remain together in the Navs G Suit (unofficially) - or in the 'stowage place' so that the fire dept could get them with 'standardisation'. Somewhere in the string would be a red flad with 'remove before flight' embossed. The Pins are 2 for the Ejection Firing Handles, (one each between the pilot and nav - near your knees), and three above your head (one) for severance and floatation (the 'alternative method'), one for Chute deploy and one for chute release (Note Warning about pullinjg this one before module landing). The alternative method has never been used successfully, as a failure of the primary ejection handles would possible not be discovered prior to aircraft/terrain impact..