I didn't answer. I was mentally calculating my chances of reaching the truck before he could catch me.

我没回答。我正在脑海里计算着在他抓住我以前我能跑回我的卡车的机会有多大。

Another reason for the two engines is if one of them breaks down, the other will ensure that the truck will reach the workshop by itself.

使用两台发动机的另一个原因是， 如果其中一台发生故障，另一台将确保卡车自行到达车间。