Here are some safety tips related to mechanical failures discussed in the Turn at the Front column.
The second most common mechanical failure mentioned in that column is a broken cable. When that happens with externally routed cables, don’t try to ride to a bike shop while holding onto your broken cable. One slip and it may easily get all tangled up in your bike, bringing it to a screeching halt and throwing you off the bike! Find a way to safely secure the broken cable to the bike before riding to help.
Similarly for flat tires, never try riding on them to the bike store, especially with a flat front tire. The moment you attempt a turn, the tire will tend to roll, sending you sprawling onto the pavement. You need to either fix the flat and pump up the tire, or get a car ride to the bike store to get it fixed.