`tmux run-shell` is primarily designed to run non-interactive shell commands within a tmux session. It's not well-suited for running interactive shell sessions.
If you want to interact with a shell session inside tmux, you would typically create a new pane or window and run a shell in that pane, which allows for full interactivity. You can do this with the `tmux split-window` or `tmux new-window` commands followed by your preferred shell (e.g., `bash` or `zsh`).
For example, to create a new horizontal split with an interactive bash session:
```
tmux split-window -h
```
You can then type `bash` to start an interactive shell session in that split.
So, while `tmux run-shell` is useful for running one-off commands, it's not intended for interactive shell sessions.