He's heard of these exercises. Personally, Sentinel used different methods to build up trust within his henchmen. Exercises like 'was that a real grenade or a dud' or 'did I fire 7 shots or 8?' They work pretty well. Weed out the weak ones pretty quickly, too.

He's hesitant, regardless. Everything he was used to was done in relative comfort - he's not even sure he wants to turn his back on Optimus. Well, whatever happens happens. Sentinel is sure he could get at least one or two good shots in if he was shot or stabbed in the back.

"I like how we had to move from the crater," he snorts.