"Everything is going to be okay." These are the words Basil had been telling himself all this time to help calm down. Everything's going to be okay. According to the unused truth album text, these are also the words he told Sunny to reassure him. Everything's going to be okay. And then the two of them hanged Mari. The whole time Sunny kept repeating those words to himself. Everything is going to be okay. Everything is going to be okay. After it was all over, he knew it was never going to be okay after what they did. But Basil kept desperately holding on to those words and the hope that it could be true. The same words that he uses to calm down are words that stress out Sunny.
All of that to say that it's a really cool detail that the Energy Meter turns from a heartrate monitor into the words "Everything is going to be okay" the closer it gets to 10.