Jack was indeed thankful. By now, he was certain the Insider had realised he couldn't die and the number of things that they could experiment... no, Jack had spent a few sleepless nights already running through things in his mind. "All the more to keep screwing with us," Jack replied. "Take some for experiments and do things, take others and just hold us. What next?" What next indeed.
No, Jack wasn't smiling and no, he wasn't sliding his arms around the other man to keep him close, nor was his nose pressing against Ianto's temple, breathing in his scent. He wasn't doing any of those things except, well, maybe he was. Because he needed to just hold onto Ianto and Jack had a feeling Ianto felt the same. "I'm safe and I'm fine. I promise," Jack murmured into Ianto's hair; if he didn't say it, they'd never discuss it.
Jack didn't do emotions and Ianto was too British.