Student or Learner
Despite being so tired that I thought I might dissolve right there on the grimy floor, I laughed. So did he, and once we started, it was like we couldnít stop. I knew it was just that weird mix of relief and fatigue, but it felt so good to laugh with him that I didnít care.
Hard to say without knowing the history between these two! 'Dissolve' can be used as an abbreviated form of 'dissolve in[to?] tears'. Perhaps that's it - though I have no idea what the griminess of the floor might have to do with it.