Rather than cleverly broke your foot? I've been on crutches in the past, get some good speed up and you'll be faster than walking without a break - until you break the toes on your other foot, hitting the crutches.

I'm trying to remember where the BA flights leave from in T3. The walk from Short Stay to the terminal isn't too bad, you'll need to walk through arrivals and the BA flights check in at the first zone you arrive at. To departures is a quick trip up the escalator, and to the lounge is another couple of hundred metres.

Some of the flights in T3 are a good ten minutes of walking without injury; isn't this a case when you'd be entitled to special assistance?

Overall, it's easier than being in T5 unless you are leaving from a distant gate.