I don't get how people manage this kind of damage as there's a fair bit of length to the wiring and if you can get your feet to the multiplugs from sitting in the back you must be some kind of freak as they're right at the front and the seats frame design stops you getting to it. Stuffing bags and other items can do it but not a human leg/foot.
DON'T make ANY connections to the SRS circuit with the battery connected and the SRS computer in an unlocked state. This is how accidental triggers happen and it can detonate the passenger dash, steering wheel, pre-tensioners and the seat bag units which will cost mega money to replace along with the SRS computer... oh, and do you some serious harm in the process should you disrespect it!
Do you know 100% which wires connect where? If so it's a good start and disconnecting the battery prior to any repairs will surfice but you get one wire wrong and it is going to cost you. Also do not use nasty crimps, scotch locks or choc-bloc connections. Make a good soldered joint and weather proof it accordingly using a quality heat shrink.
Mick